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THE STABILIZATION OF TUNGSTEN(VI) ALKYLS, ALKYLIDENES, 
AND HYDRIDES USING A BIDENTATE BIS-AMIDE LIGAND 



By 
DANIEL D. VANDERLENDE 



A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL 

OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT 

OF THE REQUIREMENTS FOR THE DEGREE OF 

DOCTOR OF PHILOSOPHY 



UNTVERSITY OF FLORIDA 
1994 



-.._ 



,\/27$ 



ACKNOWLEDGEMENTS 

The people deserving thanks from the author for the completion of this dissertation 
are innumerable. A great debt is owed to Dr. Jim Boncella, who has guided the author 
through this adventure. The lessons taught by Jim will have an influence on the rest of the 
author's life. He not only challenged and motivated the author, he also brought out the best 
in the author's golf game, teaming with Larry Villanueva and William Vaughan to win the 
1993 Analytical Open. 

Special thanks goes to Dr. Khalil Abboud. Dr. Abboud solved or helped the author 
solve all of the crystal structures reported in this dissertation. He taught the author 
everything the author knows about crystallography. The author is grateful for the patience 
and enthusiasm Dr. Abboud showed throughout the research which was the basis for this 
dissertation, exemplified by the eleventh hour structure included in Chapter 4 . 

There were many people who passed through the Boncella lab during the author's 
tenure. Everyone of these people played a role in the completion of this dissertation. 
Those who have since moved on, Larry, Laura Blosch, Scott Gamble, and Gaines Martin, 
were positive role models who taught by example how to work hard in a fun group 
environment. Will Vaughan has been a constant source of fun, excitement, and intellectual 
stimulation over the past four plus years.' The author would also like to remember all the 
other members of the Boncella group who have made research so stimulating; Percy 
Doufou, Jerrold Miller, Mary Cajigal, Justine Roth, Jon Penney, Steve Wang and Faisal 
Shafiq. Who could ever forget Tegan Eve and Melissa Booth? 

Special thanks also goes to Mike Cruskie and Chris Marmo who have been great 
friends and fellow chemists over the years. A special thanks also goes to the Talham 
group, especially John Pike and Houston Byrd, who both shared their unique perspectives 

ii 



on life with the author. The author is also indebted to the people who made the research 
possible on a daily basis; Dr. King, Charlie Cromwell, Rudy and Vern. 

None of this would have been possible without my parents who instilled in their 
son the desire to never be satisfied with past accomplishments. The author would like to 
acknowledge the love and devotion of the "Coach". He was always there for the author, 
displaying undying devotion and loyalty. Lastly, the author would like to acknowledge his 
wife Michelle, who has been the driving force behind the completion of this dissertation. 
Michelle has always believed that there is nothing her husband cannot accomplish, and that 
belief has motivated the author to strive to be more than he ever thought he could be, 
because maybe she is right. 



in 



TABLE OF CONTENTS 

ACKNOWLEDGEMENTS H 

ABSTRACT vi 

CHAPTERS 

1 BACKGROUND AND INTRODUCTION 1 

1.1 High Oxidation State Transition Metal Chemistry Involving Ligand Metal 
Multiple Bonds 1 

1.2 Olefin Metathesis and Olefin Metathesis Polymerization 4 

1.3 Chelate Stabilized Alkylidenes 8 

1 .4 Polydentate, Polyanionic Ligands 11 

2 SYNTHESIS OF BIS-AMIDE CHELATE LIGANDS AND LIGAND 
METAL COMPLEXES 13 

2.1 Preparation of Bidentate Ligands 13 

2.2 Synthesis of New Ligand-Metal Complexes 16 

3 SYNTHESIS AND REACTIVITY OF W(VI) ALKYLS AND 
ALKYLIDENES 27 

3.1 Background Information on W(VI) Alkyls and Alkylidenes 27 

3.2 Synthesis of W(VI) Bis- Alkyl Complexes 29 

3.3 Alkylidene Formation From Bis-Alkyl Complexes 36 

3.4 Metathesis Activity of W(NPh)(CHCMe3)(PMe 3 )[(Me 3 SiN)C6H4], 36 46 

4 FORMATION OF W(VI) HYDRIDES FROM THE BIS-ALKYL 
COMPLEXES 55 

4. 1 High Oxidation State Transition Metal Hydride Complexes 55 

4.2 Preparation of W(VT) Hydride Complexes 55 

4.3 Reactivity of the Dihydrides 69 

5 EXPERIMENTAL 75 

APPENDICES 87 

A TABLES OF NMR DATA 88 

B TABLES OF CRYSTALLOGRAPHIC DATA 103 

REFERENCES 147 



IV 



BIOGRAPHICAL SKETCH 153 



Abstract of Dissertation Presented to the Graduate School 

of the University of Florida in Partial Fulfillment of the 

Requirements for the Degree of Doctor of Philosophy 

THE STABILIZATION OF TUNGSTEN(VI) ALKYLS, ALKYLIDENES, 
AND HYDRIDES USING A BIDENTATE BIS-AMTDE LIGAND 

By 

Daniel D. VanderLende 

December, 1994 



Chairman: James Boncella 
Major Department: Chemistry 

The synthesis of a number of W(VI) complexes stabilized by bis-amide chelate 
ligands was achieved with the goal of preparing new olefin metathesis polymerization 
catalysts. Addition of Li 2 [(NSiMe3)2C6H4] 2, to W(NPh)Cl4(OEt2) yields 
W(NPh)Cl2[(NSiMe3)2C<5H4] 14. A single crystal diffraction study of 14 reveals that it 
crystallizes in the space group P 2]/n with a = 10.294(2) A, b = 17.859(3) A, c = 
12.565A, (3 = 104.15(2)°, V = 2384.6(8) A3, Z = 4. The structure of 14 is unique in that 
the ligands phenyl ring is in close contact with the metal center, with a fold angle of 53°. 
Addition of PMe3 to 14 affords the purple mono-adduct, 

W(NPh)Cl2(PMe3)[(NSiMe 3 )2C6H4] 21. A single crystal diffraction study of 21 reveals 
that it crystallizes in the space group P_i with a = 9.562(1) A, b = 10.277(1) A, c = 
14.920(2) A, a = 82.15(1)°, (3 = 80.18(1)°, y = 80.41(1)°, V = 1415.6(3) A3, Z = 2. 
Compound 14 can be alkylated to give the corresponding bis-alkyls, 
W(NPh)R2[[(NSiMe3)2C6H4]. The 14 electron bis-alkyl compounds show no evidence of 
a-agostic W-H-C interactions and have ^Ca-H values between 120 and 130 Hz. 



VI 



W(NPh)(CH2CMe3M(NSiMe3)2C6H4] 25 can be heated in the presence of excess PMe3 
to give the new alkylidene complex, W(NPh)(CHCMe3)(PMe3)[(NSiMe 3 )2C6H4], 36. 
Compound 36 crystallizes in the space group P 2\lc with a = 16.1 16(3) A, b = 1 1.340(2) 
A, c = 17.960(4) A, (3 = 106.28(2)°, V = 3151(1) A 3 , Z = 4. The x-ray structure of 36 
reveals a unique square pyramidal structure with the alkylidene carbon in the apical 
position. Compound 36 is an active ROMP catalyst, polymerizing twenty five equivalents 
of norbornene in ten minutes at room temperature. The reactivity of the catalyst can be 
altered by the addition of excess PMe3 to the reaction mixture. 

W(NPh)(CH2CMe3)2[(NSiMe3)2C6H4] 25 reacts with molecular hydrogen in the 
presence of PMe3 to give the seven-coordinate dihydride complex, 
W(NPh)H2(PMe3)2[(NSiMe3)2C6H4] 39. The dihydride reacts with two equivalents of 
ethylene or styrene to give the W(IV) olefin complexes W(NPh)(r| 2 - 
C2H4)(PMe3)2[(NSiMe3)2C 6 H4] 46, and W(NPh)(r|2- 

CH2CHPh)(PMe3)2[(NSiMe3)2C6H4] 47. The olefin complexes react with H 2 , 
hydrogenating the olefin and forming the dihydride, 39. 



vu 



CHAPTER 1 
BACKGROUND AND INTRODUCTION 



1.1: High Oxidation State Transition Metal Chemistry Involving 
Metal Ligand Multiple Bonds. 

There has long been an interest in the isolation of high oxidation state transition 
metal complexes. 1 The term high oxidation state transition metal refers to transition metals 
which are in their highest or nearly highest oxidation state. Throughout this discussion, 
high oxidation state transition metals will usually refer to transition metals with zero d 
electrons, or d° complexes. The applications of high oxidation state transition metal 
complexes are innumerable. A plethora of reactions are catalyzed by such compounds 1 - 2 
oxidations, metathesis, polymerizations and many organic transformations. Therefore, the 
synthesis of novel compounds and investigation of their properties and reactivity are 
essential in order to expand our understanding of high oxidation state transition metal 
chemistry. 

High oxidation state transition metals were being used in many applications long 
before the intrinsic characteristics or the structure of discrete molecules were known. 3 In 
other words, high oxidation state transition metal complexes have been used as 
heterogeneous catalysts and homogeneous catalysts for decades, but, in order to expand 
our understanding of the reactions catalyzed by these compounds, the identity of the 
discreet molecules must be known. Often times, the active species in the reaction is 
different that the starting compound, and hence the structure of the active species is 
unknown or unproven. 3 Many high oxidation state transition metal complexes contain 
multiply bonded atoms; nitrogen, oxygen, and carbon are the most common. 2 Also, the 
active species in many catalytic processes are postulated to contain metal-ligand multiple 



bonds. 3 ' 4 Often, these multiply bonded ligands are the key to the reactivity or stability of 
the molecules. Therefore, the synthesis and structural elucidation of new multiply bonded 
ligand-transition metal complexes will always be relevant. 

Examples of transition metal oxo 5 [O] 2 ", imido 6 [NR] 2 ~ and nitrido 7 [N] 3 ~ 
complexes are numerous. Books and reviews on these types of ligands can be found 
throughout the literature. The chemistry of high oxidation state transition metal-carbon 
multiple bonds, alkylidenes [CHR] 2 " and alkylidynes [CR] 3 ", are rapidly becoming better 
understood, yet relatively few examples compared to oxo or imido complexes are known. 8 
The bonding in oxo, imido, and alkylidene complexes share some common characteristics. 
They all involve a metal ligand G-bond and one or more rc-bonds between the ligand/? 
orbitals and the empty metal d orbitals. 1 ' 8 ' 9 In oxo and imido complexes, a lone pair of 
electrons can also form a second 7t-bond to the metal center. In imido complexes, this is 
evident in the fact that for most of the structurally characterized compounds, the M-N-C 
bond is nearly linear, greater than 160 . 1 ' 8 The bond is considered a six-electron donor and 
a di-anionic contribution from the ligand, creating a formal bond order of 3, Figure 1.1. 
In alkylidenes, there is not an extra pair of electrons, therefore, the bond is considered as 
one a and one 7t-bond, a four-electron [-2] donor, with a formal a bond order of 2, Figure 
1.2. This interaction between the ligand ji and metal d 



M=N R 




Figure 1.1. Figure 1.2. 

Bonding in imido complexes. Electronic interactions in alkylidenes. 



orbitals leads to a stabilization of the complex due to electron donation to the empty orbitals 
on the dP metal center. 1 ' 9 For this reason, many of the known high oxidation state 



compounds contain one of the multiply bonded ligands mentioned. Figure 1.3 shows 
how the number of publications in this field of research has grown in just a few decades. 1 
It should be recognized that the table does not include oxo complexes, work on which is 
published at roughly an order of magnitude greater than the others combined. 



200 



I 
1 
1 



1 




100 - 



1960 1965 1970 1975 1980 1985 

Period Ending 
Figure 1.3. Graph of imido and alkylidene publication rates. 



It would be difficult and unnecessary to give a complete review of high oxidation 
state transition metal complexes with multiply bonded ligands in this introduction. 
Therefore some restraints will be put on the background information. The information 
relevant to the research that was carried out pertains to W(VI) oxo, imido, and alkylidene 
compounds. Therefore this discussion will be limited to examples of these and other 
closely related compounds for direct comparison to the tungsten derivatives. Although 
numerous new W(VI) imido and a few oxo compounds were isolated as a result of this 
work, in every instance they behave as spectator ligands. They play an important role in 
the electronic stabilization of the complexes but do not participate directly in any reactions. 
This will become more evident in the discussion of the research results. 



1.2 Olefin Metathesis and Olefin Metathesis Polymerization 

The initial goal of this project was the isolation of thermally stable, coordinatively 
unsaturated alkylidene complexes. These new complexes were then intended to catalyze 
specialized metathesis polymerization reactions. And although this goal was attained in 
part, many novel, unrelated aspects of high oxidation state chemistry were observed along 
the way. 

In just the last two decades, the important role of transition metal alkylidene 

complexes in olefin metathesis reactions has been thoroughly investigated. 10 ' 11 The olefin 

metathesis reaction, in general, can be described as the net breaking of carbon-carbon 

double bonds, and forming two new carbon-carbon double bonds Figure 1.4. The 

R R" 

R H H R" \ / 

\s V • , > < 

transition metal 
catalyst 



H 
H 


+ 


H 

H 



R' H H R'" 



< 



R R" 

Figure 1.4. Scheme showing the net conversion observed in 
olefin metathesis reactions. 



overall result is the exchange of substituents on the olefins. It was the suggestion by 
Herrison and Chauvin 12 in 1970 that the mechanism for olefin metathesis involves an 
alkylidene bond Figure 1.5. An olefin can then coordinate to the electrophilic metal 
center. An intermediate metallacyclobutane is formed which can either cleave to give the 
original alkylidene/olefin complex or cleave to give a new olefin complex. 

rMi < ' V/\ [M] <^ 




y=<y "S6 H H > = =< , 

ST R" R^H R R " 

Figure 1.5. The Chauvin mechanism for metathesis involving metal alkylidenes with 
arrows depicting the direction of electron flow for productive metathesis. 



This mechanism gained wide acceptance and seemed quite plausible for systems such as the 
popular olefin metathesis catalyst, WOCl4/EtAlCl2, where the formation of an initial 
tungsten ethylidene complex 3 is easy to rationalize Figure 1.6. 

o 

ci^y^-^ -CH3CH3, ci> 



o 

w^ + 2EtAlCl 2 < MC[ & 



ci / 



cS 



w <^ 



H 
CH 3 



c/ 

Figure 1.6. The proposed formation of an ethylidene complex 
in the WOCI4/E1AICI2 system. 

Postulation and speculation about alkylidene formation officially ended on July 27, 
1973, when Schrock 13 at I. E. du Pont Central Research synthesized 
Ta(CHCMe3)(CH2CMe3)3. Since that time, numerous other alkylidene complexes have 
been isolated and have been shown to be active catalysts for metathesis and metathesis 
polymerization reactions. In the early 1980s, tungsten and molybdenum alkylidenes 
received special attention since they are highly active olefin metathesis catalysts. The fields 
of olefin metathesis and olefin metathesis polymerization received a boost in 1989 when 
Schrock published the detailed synthesis 14 of W(NAr')(CH-t-Bu)(OR) 2 (Ar' = 2,6-'Pr 2 Ph; 
OR = O-t-Bu, OCMe 2 (CF 3 ), OCMe(CF 3 ) 2 ). The W(NAr')(CH-t-Bu)(OCMe(CF 3 ) 2 )2 
derivative has proven to be the most active alkylidene catalyst to date. Recently, the 
molybdenum r-butoxide derivative has become available commercially from Strem 
Chemical, through Catalytica, albeit for a hefty price. 

Schrock's tungsten and molybdenum catalysts have some unique features which 
lend to the high reactivity which has been observed. In order to design a new or better 
catalyst, certain features must be retained. Obviously Schrock's catalyst involves Group 
(VI) metals in the 6+ oxidation state. That the catalysts are only four coordinate is essential 
since coordination of the olefin to the metal center is the initial step in metathesis. The 
imido moiety's role is crucial. There are examples of oxo-alkylidene's where the role of 



the oxo is identical to the imido. 15 Of the known tungsten and molybdenum alkylidenes, 
examples without an imido or oxo ligand are less common. 16 

The imido functionality offers a great electronic stabilization to the metal center. 
The bonding can be thought of as a a bond and two 7t bonds, the second n bond arising 
from donation of the lone pair of electrons on the imido nitrogen to an empty metal d 
orbital. The imido functionality can also stabilize the complex by adding steric bulk to the 
metal center. Most of the known alkylidene complexes contain 2,6-disubstituted aryl imido 
ligands. 8 The other substituents also contribute to the steric bulk around the metal center. 
All of the alkoxide substituents are rather bulky, and the alkylidene substituent is usually a 
bulky alkyl group. The steric bulk is necessary since these complexes are known to 
dimerize forming bridging alkylidenes. 8 The bulky metal center reduces the probability of 
this transformation. The steric bulk also plays a role in the formation of the alkylidene 
itself. A large percentage of the known alkylidenes are formed through a-hydrogen 
abstraction reactions from dialkyl precursors or intermediates. 8 The steric bulk helps 
promote the a-abstraction, usually of a bulky alkyl substituent. The reactivity of the 
alkylidene catalysts is observed to increase as the electron withdrawing nature of the 
alkoxide is increased, O-t-Bu < OCMe2(CF3) < OCMe(CF3)2). 8 This is intuitive since the 
electron withdrawing nature of the alkoxide would make an already electron deficient 
molecule more so, thereby increasing the olefin affinity, which, as was mentioned before, 
is the initial step in olefin metathesis. 

As was mentioned earlier, these alkylidene catalysts can facilitate the polymerization 
of olefins. 10 >! 1 The most common metathesis polymerization reaction is Ring Opening 
Metathesis Polymerization (ROMP). 10 The ROMP reaction is driven by the relief of ring 
strain in cyclic olefins. Since olefin metathesis reactions are actually series of equilibria, 
the opening of a strained ring prohibits the reverse reaction, driving the polymerization. 10 
The overall ROMP reaction is shown in Figure 1.7. A large volume of work has been 
done on the ROMP reaction. Norbornene, NBE, is commonly used as the olefin since it is 



readily polymerized by a large number of catalysts. Schrock and Grubbs have 
demonstrated that many ROMP reactions are living' polymerizations. 17 

A unique olefin metathesis polymerization reaction which was developed here at the 
University of Florida involves acyclic dienes. 1 ^ The net reaction for acyclic diene 

H R H 

= "h 



H 
M=C( + 
R 



o 



^ M 




R 




Figure 1.7. The ring opening metathesis polymerization of a cyclic olefin. 



metathesis polymerization (ADMET) can be seen in Figure 1.8. The equilibrium is 
driven toward polymer formation by the removal of ethylene, or another small, volatile, 
olefinic molecule, from the reaction mixture. ADMET polymerization has long been the 
driving force in the research efforts of the group. ADMET reactions are best carried out in 
neat monomer in order to maximize the olefin concentration and to prevent side reactions. 
One of the major hindrances in this chemistry is precipitation of the reaction mixture before 
the polymerization can be carried to high molecular weight. As an example, when 
poly(octene) reaches twelve connections in neat 1,9-decadiene, precipitation occurs. 
Performing the reaction at a temperature above the melting point of the polymer would 
alleviate this problem. However, at this point, the thermal stability of the catalyst becomes 
crucial. Schrock's catalyst is thermally unstable, so, although the Schrock catalyst has 
proven efficient for ADMET, achieving high molecular weight polymer is difficult. 



M: 



H 

:Q + 

R 




+ C 2 H, 



Figure 1.8. The ADMET Polymerization of 1,9-Decadiene 



8 



The principles of ADMET have also been applied to depolymerizing unsaturated 
polymers. 19 Since all the steps of ADMET are reversible, reacting the polymer, another 
olefin, and catalyst should depolymerize a poly-ene such as polybutadiene. Success has 
been found when polybutadiene is depolymerized using Schrock's catalyst and end-capped 
with silylenes. This reaction will be discussed more in Chapter 3. 

Although the Schrock catalyst described above represents the ideal at this time, 
there are shortcomings involved in its preparation and reactivity. From first-hand 
observations, it has been observed that the preparation of Schrock's catalyst is a lengthy, 
patience-trying procedure. Not only are there multiple steps involved, but the yields are 
low and some of the reagents are far from inexpensive. Secondly, once synthesized, the 
catalysts, especially the fluorinated alkoxides, are particularly air/moisture sensitive. This 
aspect of its reactivity also translates into an intolerance of certain functional groups. A 
common phrase heard in polymer laboratories is "The catalyst was poisoned...". Adding 
to the drawbacks of Schrock type catalysts is their thermal 'instability'. There are polymer 
systems in which heating the reaction mixture would be advantageous toward achieving 
maximum yields or molecular weights; however, Schrock's catalysts general decompose 
over the temperature range of 60-80 °C. 20 So, although the introduction of Schrock's 
catalysts opened up vast areas in metathesis and polymerization, there is still a great need 
for new catalysts which are easier and less expensive to prepare. 

1.3 Chelate Stabilized Alkylidenes 

An intuitive approach to the synthesis of an alkylidene compound with a greater 
thermal stability would be to use chelating ligands somewhere in the molecule. The use of 
a chelating ligand may also produce interesting stereochemical properties in the metathesis 
reactions. This approach has been investigated by Schrock, Grubbs, Boncella, VanKoten 



and others. There are a number of options as to where to apply 'chelates' in these 
complexes. Schrock has made a series of diolate complexes 21 of the type 
Mo(CHCMe2Ph)(NAr)(diolate) Figure 1.9. Although no comment is made about 




(R4tart)Mo(NAr)(CHMe 2 Ph) 
R = phenyl, naphthyl 



" siMe 2 Ph t-Bu' -SX- >B» 

BTNO(SiMe2Ph) 2 Mo(NAr)(CHMe2Ph) Biphenol(t-Bu) 4 Mo(NAr)(CHMe2Ph) 



Figure 1.9. Bidentate diolate complexes prepared by Schrock. 

the thermal stability, it is assumed that they are more stable than the complexes with 
monodentate alkoxides. These compounds do, however, allow for stereochemical control 
of ROMP reactions. Grubbs has taken an interesting approach by synthesizing o- 
substituted aryl alkylidenes 22 , where the o-substituent has o-donor properties and can 
chelate to the metal center, stabilizing the alkylidene Figure 1.10. 
VanKoten's alkylidenes are stabilized by chelating c-donors as well. 23 In the tungsten(VI) 
alkylidene complex, W(NPh)(C6H4-o-CH 2 NMe2)(CHSiMe3)(OSiPh 3 ), the -NMe 2 group 
on the orrto-methylene group acts as a a-donor, adding a chelate effect Figure 1.11. 



THF' 




OR' = OCCH 3 (CF 3 ) 2 
R = H, Me, i-Pr 




Figure 1.10. Grubbs' Catalyst 



■NMe 2 SiMe 3 

Figure 1.11. VanKoten's Catalyst. 



Work done here at Florida by Blosch, Gamble, and Vaughan in the research group of 
James Boncella 24 has focused on the use of the tris-chelating, mono-anionic ligand 
hydro(tris)pyrazolylborate, Tp. Six-coordinate alkylidene complexes of the type 



10 

TpM(NAr)(CHR)(X) (M = W, Mo; R = CMe 3 , CMe 2 Ph; X = CI, Br, OTf, OMe, NHPh) 
have been isolated Figure 1.12. These complexes show remarkable air and thermal 
stability, although they only show metathesis activity in the presence of a Lewis acid, 
which generates a vacant coordination site. Once again, the importance of coordinative 
unsaturation is observed. 




M = W; Mo 

Y =NAr,0 

X = CI; Br; OTf; OMe; NHPh 

R =Me;Ph 



Figure 1.12. Tridentate chelate complexes using the 
hydro(tris)pyrazolylborate hgand. 



The use of chelate ligands has provided two things to the chemistry of alkylidenes. 
First, it has produced more thermally stable alkylidenes, even air-stable in the case of the 
Tp alkylidenes. Secondly, the chelates ligands have greatly reduced the reactivity of the 
alkylidenes towards olefins. The ultimate goal of this work would be to design a ligand 
which provided stability while maintaining a high olefin affinity at the metal center. 
Obviously this would mean a coordinatively unsaturated, electron deficient molecule. A 
look back at the some of the known chelated alkylidene compounds reveals an undesirable 
trend; the chelate ligand involves a neutral G-donor interaction. In simple terms, all this 
does is clog the coordination sphere of the molecule. A more pragmatic approach would 
eliminate neutral G-donor ligands to a great extent and concentrate on the use of anionic 
ligands as chelates. The Tp ligand for example is a tridentate, mono-anionic ligand. Van 
Koten's chelate could be considered a bidentate, mono-anionic hgand. 



11 



1.4 Polydentate. Polyanionic Chelate Ligands 

An ideal ligand would be a polyanionic, polydentate ligand. Either a bidentate, di- 
anionic ligand, or a tridentate, tri-anionic ligand. There are a number of examples in the 
literature of multidentate, multi-anionic ligands. Schrock and Cummings have used a 
tetradentate, tri-anionic ligand to prepare some novel high oxidation state titanium, 25 
vanadium 25 and tantalum 26 compounds. The ligand, (Me3SiNCH2CH2)3N was used to 
stabilize an interesting terminal phosphinidene complex as well as some other high 
oxidation state early transition metal complexes Figure 1.13. Verkade 27 first used 
methyl derivatives of this ligand, (MeNCH2CH2)3N, to stabilize some group (W) and (V) 
compounds Figure 1.14. Gade 28 has used a similar ligand, H3CC(CH2NHR)3 (R = 
Me, Et, i Pr, SiHMe2, and SiMe3), to stabilize titanium complexes. This ligand has a 
carbon in the bridgehead position, avoiding the o-interaction which the nitrogen had with 
the electrophilic metal center, creating a tridentate, tri-anionic ligand, thereby decreasing the 

metal centers coordination number by one. 

PR 

Me 3 Si 



N 
Me 3 Si-l N / 




Ta — .fj— - SiMe3 



N- 



5 


t 




Y 


1— . Y 

J- / 


M = V, Ta 
Y = 0, NMe 
Z = 0, NR 


igure 1.14. Gade's 


tetradentate 




tris-anionic ligands. 



Figure 1.13. Phosphinidene 
stabilized by Verkade's ligand. 



Wilkinson 29 has employed the use of o-phenylene&arnine in the stabilization of 
tungsten (V) and (VI) compounds. One negative aspect of this particular bidentate, di- 
anionic ligand is the tendency for rearrangement of the bis-amide to an imido-amine. This 
problem could be easily overcome by synthesizing N,N'-disubstituted derivatives. This 
premise is where the present study begins. A number of novel N,N'-disubstituted 



12 

derivatives of o-phenylenediamine and 1,8-diaminonapthalene were synthesized and then- 
application as bidentate, di-anionic ligands were investigated. All of the work reported here 
involves tungsten (VI) phenylimido or oxo complexes exclusively. The high-yield 
synthesis of various tungsten (VI) phenylimido ligand stabilized complexes allows a 
convenient route into the reaction chemistry of these complexes. This work, involving the 
preparation of starting materials, will be covered in Chapter 2. Simple alkylation reactions 
allow the isolation in good yield of a series of mono- or di-alkyl complexes. Isolation of 
stable ris-bisalkyl complexes offers a look into the reaction chemistry of these compounds, 
and will be the focus of Chapter 3. Heating the bis neopentyl derivative in the presence of 
PMe3 induces a-hydrogen abstraction, forming an alkylidene and one equivalent of 
neopentane. The neopentylidene complex is an active catalyst for the ROMP of 
norbornene. The activity of the catalyst can be tailored by the addition of excess ligand to 
the reaction mixture. This will also be covered in Chapter 3. A majority of the chemistry 
found in Chapters 2 and 3 has previously been published. 30 An interesting feature of the 
alkyl complexes is that they react at room temperature with molecular hydrogen to form 
high oxidation state hydride complexes. The addition of a a-donor ligand accelerates the 

reaction tremendously as well as aides in the stabilization of the molecule. The seven- 
coordinate dihydride species formed reacts with ethylene, hydrogenating one equivalent, 
while the reduced metal species forms a tungsten (IV) ethylene complex. The reactivity of 
the alkyls towards hydrogen and olefins will be the focus of Chapter 4. 



CHAPTER 2 

SYNTHESIS OF BIS-AMIDE CHELATE LIGANDS 

AND LIGAND-METAL COMPLEXES 



2.1: Preparation of Bidentate Ligands. 



In order to pursue the use of 1,2-phenylenediarnine as a bidentate, di-anionic 
ligand, an accessible route to the synthesis of bulky N,N'-disubstituted derivatives was 
desired. A thorough review of the literature reveals surprisingly few examples of such 
compounds. The only known bisalkyl example is N,N'-dimethyl-l,2- 
phenylenediamine, 31 which is prepared through a tedious, dangerous, multi-step synthesis. 
There are examples of other disubstituted derivatives such as -S(0)2tolyl (tosyl) 31 and 
-C(0)Ph. 32 A slight discrepancy in the literature was discovered for the case of N,N'- 
bis(trimethylsilyl)-l,2-phenylenediamine, l,2-(Me3SiNH)2C6H4, 1. Before this was 
discovered, however, a nearly quantitative one-step synthesis of 1 was discovered eq 
2.1. (9-phenylenediamine was dissolved in Et20 on as large a scale as available 

Me 3 Si 



f^Y NH2 



1. 2eq. Me 3 SiCl 

2. 2 eq. NEt 3 

Et 2 0, °C 



\ 



H 
H 



eq2.1 



./ 



Me 3 Si 

glassware would allow. A slight excess of two equivalents of Me3SiCl was added, 
forming a white precipitate, presumably the hydrochloride salt. A slight excess of two 
equivalents of NEt3 was added to the slurry. The solution became yellow amidst the solid. 
Filtering and removing solvent gave a bright yellow solid in greater than 95% yield. It is 



13 



14 

important to note that the slightest impurity causes formation of a yellow oil, partly due to 
the low melting point (29 °C) of 1. 

The preparation of 1 described above differs greatly from the literature methods. 
Compound 1 was first reported in the literature in 1960 by Birkofer. 33 Birkofer refluxed 
o-phenylenediamine, two equivalents of Me3SiCl and NEt3 in toluene followed by a 
fractional distillation to give a moderate yield of 1. In 1970, West 34 reported refluxing o- 
phenylenediamine, hexamethyldisilazane, and a catalytic amount of MesSiCl in THF for 24 
hours. Fractional distillation using a spinning band column gave an 80% yield of 1. West 
also reported that addition of MeLi to 1 in THF solvent caused rapid 1,4 anionic 
rearrangements to occur. 34 This finding was an important consideration when solvents for 
the ligation chemistry were chosen. In 1985, Lappert reported heating o- 
phenylenediamine, Me3SiCl, and NEt3 in toluene (with no mention of Birkofer). 35 
Lappert then treated 1 with MgBu2 to give the deprotonated dimer, [Mg{|i- 
N(SiMe3)C6H4N(SiMe3)-o}(OEt2)]2- Maatta 36 reports another preparation in 1992. 
Here, o-phenylenediarnine is deprotonated with two equivalents n-BuLi, followed by 
addition of two equivalents of Me3SiCl. The product, 1, is isolated as a yellow oil by 
vacuum distillation in 80% yield. One concern that this report brought out was that when 
(Me3SiNH)2C6H4, 1, was allowed to react with WClg, two equivalents of HC1 and two 
equivalents of Me3SiCl were lost, forming a bridging di-imide eq 2.2. 





1. CH 2 C1 2 ™ 

2. THF Cl^N N^Cl 

w w eq l.i 

thf' £ ci a-^ THF 



From Lappert's account, 1 should be susceptible to deprotonation. Addition of two 
equivalents of n-BuLi to 1 afforded the white salt Li2(Me3SiN)2C6H4, 2. Interestingly, 
the salt was soluble in C6D6 and the ! H NMR of 2 verifies that there were no N-H 



15 

protons. The salt, however, was extremely moisture sensitive and spontaneously ignited 
upon exposure to air, hence prolonged storage was difficult. Before the application of 1 
and/or 2 as a ligand will be addressed, the synthesis of other potential ligands will be 
discussed. 

Although the high yield synthesis discussed for 1 might seem applicable for a series 
of silyl chlorides, it did not prove to be. However, when refluxing hexanes were used as 
the solvent instead of Et20, a series of silylated compounds were isolated in high yield. 
This general route applies to making the -SiMe2Ph, 3; -SiMePh2, 4; or -SiMe2-?-Bu, 5, 
derivatives of o-phenylenediamine. Another derivative of o-phenylenediamine was 
prepared in this manner, 4,5-dimethyl-l,2-(Me3SiNH)2C6H2, 6. This route was also 
utilized to prepare l,8-(Me3SiNH)2CioH4, 7, in high yield and on a large scale from 1,8- 
diaminonaphthalene and two equivalents of both Me3SiCl and NEt3. An asymmetric 
disubstituted o-phenylenediamine derivative, l-(PhNH)-2-(Me3SiNH)C6H4, 8, was 
synthesized similarly from N-phenyl-o-phenylenediamine, Me3SiCl and NEt3. 

Attempts to synthesize dialkyl derivatives of o-phenylenediamine proved less 
successful. In an attempt to synthesize l,2-( i PrNH)2C6H4, o-phenylenediamine was 
slurried with excess sodium acetate in a cold acetic acid/acetone/water mixture. Excess 
NaBH4 was added slowly. After neutralizing the solution with NaOH and isolation of 
products, a 1:1 mixture of products was formed. They were separated by flash 
chromatography and analyzed. l,2-0PrNH)2C6H4, 9, was isolated as a colorless oil. The 
other product was a heterocyclic compound, 10, which is shown in eq 2.3. The 
heterocycle most likely forms by an attack of one imine nitrogen on the other imine carbon, 
followed by a 1,3 proton shift. Altering the reaction conditions did not change the relative 
yields of 9 and 10. The *H NMR of 10 is shown in Figure 2.1. Since formation of the 
7-membered heterocylce seemed unavoidable in this system, the same reaction was 
attempted using 1,8-diaminonaphthalene. Here, the formation of a 6-membered 
heterocycle might be less likely due to the strain involved in one imine attacking 



16 




NH, 



NH, 



1. acetic acid/H20 

2. sodium acetate 

3. acetone ^ 




N= CMe, 



:CMe, 



l.NaBH 4 
2. NaOH 





eq2.3 



10 

the other. A mixture was not observed. A 90% yield of a 6-member heterocycle, 11, was 
the only compound isolated eq 2.4. This compound probably arises from attack of the 
imine carbon on the lone pair of electrons from the nitrogen, followed by a 1 ,3 proton 
shift. Changes in the reaction conditions did not afford any of the desired diamine. 



NH, 



NHo 




1. acetic acid/H20 

2. sodium acetate 

3. acetone 

4. NaBH 4 

5. NaOH 




eq2.4 



11 



2.2: Synthesis of New Ligand Metal Complexes. 

Addition of these new ligands to metals was the next step in the project. Two 
starting materials were initially chosen as trial compounds, WOCI4, which was readily 
available, and W(NPh)Cl4(OEt2). W(NPh)CU(OEt2) can be prepared in high yield from 
the addition of PhNCO to WOCI4, resulting in the loss of CO2. The ligand chosen for the 
majority of the work reported was l,2-(Me3SiNH)2C6H4, 1. There are two simple routes 
available for the addition of the ligand to the metal center. First, the ligand could be doubly 



17 



c 



< 



X X 



^2 z^ 



^T 



a* 



x 



^ -! 



"o 
o 

B 

o 
J3 

■p 

<U> 
l-< 

O 



o 



o 



e4 

4) 

u 

a 



\\ // 



18 

deprotonated and then added to the metal center in a simple metathesis reaction, forming the 
ligand complex and two equivalents of a chloride salt. The other route would be to add the 
diamine ligand directly to the metal, losing HC1 either spontaneously or through addition of 
a base such as NEt3. The first route proved the more successful, and the second route was 
attempted with minimal success. 

An Et20 solution of WOCI4 was added to 2 at -78 °C. Work-up afforded a 
moderate yield of WOCl2(Me3SiN)2C6H4, 13, eq 2.5. Studies of the reaction chemistry 
of this compound were not undertaken since isolating pure 13 is extremely 

Me3Si MesSi 





eq2.5 



difficult. Altering the reaction conditions did not alleviate this problem. Attempts are 
currently underway to alter the starting W=0 complex and allow cleaner isolation of 
products, thereby allowing a thorough study of the reactivity of 13 a . 

In a similar reaction, W(NPh)CU(OEt2) was allowed to react with 2 at -78 °C, 
which afforded W(NPh)Cl2(Me3SiN)2C6H4, 14, as an orange-red powder. The bis- 
amido complex, 14, was also prepared on a large scale by deprotonating the diamine in 
situ. This method proved the most successful in preparing 14 in high yield eq 2.6. With 
an easy, large scale, high yield synthesis, 14 was an excellent starting point to investigate 
the reactivity of these chelated complexes. The electron count of the tungsten is formally 
considered to be 14 electrons, considering the imido as a 6 electron donor with the amide 
bonds contributing 1 electron each to the total electron count. The electronic donation of 



a William Vaughan has undertaken the synthesis of other W=0 complexes to be used as precursors for the 
addition of the ligand, 1. These W=0 complexes have 'softer' substituents and would presumably be more 
tolerant to metathesis. 



19 

the bidentate ligand is unclear, the nature of which could make the molecule a 14e-, 16e- or 
18e- complex. 



Me 3 Si 




M 



N 



H 

H 



2 eq n-BuLi 



Me 3 Si 



Me 3 Si 




N. 



*T 



Li 
.Li 



/ 

Me 3 Si 

"- 2- in situ - 1 



N 
Clxll/Cl 



+ 

cr 

OEt 2 



/ t x a 



Me 3 Si 




KLa 



W e q2.6 
Me 3 Si 14 



X-ray quality crystals were obtained by dissolving 14 in toluene and cooling to -10 
°C. The thermal ellipsoid plot of 14 is shown in Figure 2.2, while selected bond lengths 
and angles are found in Table 2.1. The geometry of the molecule is square pyramidal 
with the imido nitrogen in the axial position. The W atom lies .58 A above the plane 
defined by the two amido nitrogens and the two chlorides. This is similar to the crystal 
structure of W(NPh)Cl4(OEt2), which is octahedral with the imido cis to all four chlorides. 
The imido nitrogen bond length is 1.730(10) A, which is well within the range of other 
imido complexes where the imido group is considered to be a six electron donor because of 
donation of the lone pair of electrons on the nitrogen to an empty d orbital on the metal 
center. One feature of the structure of the molecule that is quite surprising is the 
'orientation' of the ligand. The phenyl group of the bis-amide ligand is distorted and bent 
toward the metal center. The dihedral angle between the plane of the C1-C6 ring and W, 
Nl, N2 is only 130°, as if there were a metal-olefin type interaction between the W and the 
phenyl ring of the ligand. The complement of this angle is referred to as the 'fold angle', 
50 °, and is quite diagnostic when compared to other compounds. The interaction appears 
quite significant; the distances between W and CI and W and C2 are only 2.58(1) A. 
Although this is greater than the W-C bond length in high oxidation state tungsten alkyl 
complexes, it is still within the vanderWaal's radii. In the few compounds that are known 
with this type of ligand, the distances are much greater (>2.80 A). 29 > 3 7 There are only a 



20 




•d 



CO 

a 

2 
p 

P< 

o 



<x 5 
o 3 



oH 

3 o 

s I 

O "t3 
co U 

■S<H 

•— H 

I ( 

•a 



3 
(31! 



21 

few examples of structures of o-phenylenediamido-type ligands. 2 9,37,38 None of these 
structures appear to have an interaction between the ring carbons and the metal center. If 
the ring is in fact acting as a two electron donor, the electron count on the metal would now 
be 16e-. 

Table 2.1: Selected Bond Lengths (A) and Angles (°) for compound 14. 

1-2 1-2-3 



Cll 


W 


C12 


2.383(4) 


82.9(2) 


C12 


w 


Nl 


2.387(4) 


150.5(3) 


Nl 


w 


N2 


1.951(11) 


83.9(4) 


N2 


w 


N3 


1.952(11) 


110.2(5) 


N3 


w 


CI 


1.730(10) 


137.4(4) 


CI 


w 


C2 


2.582(13) 


31.9(4) 


C2 


w 


Cll 


2.582(13) 


117.2(3) 


Nl 


Sil 


C13 


1.768(10) 


108.4(7) 


N2 


Si2 


C16 


1.781(12) 


106.0(7) 


CI 


Nl 


W 


1.42(2) 


98.8(7) 


C2 


N2 


w 


1.40(2) 


99.4(8) 


C7 


N3 


w 


1.39(2) 


166.2(9) 



Analogies can be made to some other types of compounds where similar bonding 
exists. Peterson 39 solved the crystal structure of a Cp2Zr chelated bis-amido complex in 
which the distances between the (3-carbons and the zirconium are 2.612(3) A and 2.603(3) 
A. Peterson claims that this close interaction is due to donation from the filled 7t-orbital of 
the C=C bond to the empty d-p- orbital on the zirconium as shown in Figure 2.3. 
Rothwell 40 observed similar results with quite similar bond lengths, in the 2.40-2.60 A 
range, for other enediamido and enamidolate chelate compounds of zirconium, titanium and 
tantalum as shown in Figure 2.4. These compounds, including 14, not only have close 
contact distances, but also have abnormally large 'fold angles'. The compounds prepared 
by Rothwell and Peterson have fold angles between 35 and 50 °. Rothwell also measured 
the AG^'s for the barrier to 'flip' these enediamido metallacycle rings. The AG^'s were in 
the 13-16 kcal/mol range. 40 This type of 'flip' would not be observed in a molecule such 



22 



as 14 since the molecule does not have a mirror plane through the metal center. Both 
Rothwell and Peterson also point out the fact that although the M-Cp bond lengths are 
longer than normal for similar M-R complexes, they are within the range of M-C bond 
lengths in M-Cp complexes. Typically, W-Cp metal-carbon bond lengths are between 




R 



R 



R' 
I 

A y» 0Ar 



I— *~M 

"*"* N N QAr R ' = *?• Ph ' tBu 



M = Ti, Zr, Hf 
R = CH 3 , CH 2 Ph 



Figure 2.3: 

A zirconacene enediamido complex. 



R' 
Figure 2.4: 

Enediamido complexes of group 4 metals. 



2.3 and 2.45 A. This is shorter than the 2.58 A observed for 14, and does not fit as well 
with the comparisons suggested by Rothwell and Peterson. Lappert has observed similar 
behavior for some bidentate, di-anionic oxylidene complexes of some bis-cyclopentadienyl 
group 4 and 5 metals. 41 The metallacycles in these compounds also displayed a significant 
interaction with the metal center, having fold angles between 41° and 53 °. 

Continued investigation of the use of these chelating bis-amide ligands led to the 
synthesis of other new compounds. There were two goals for preparing new derivatives of 
these bis-amide derivatives, less solubility and more crystallizability. To this end, 1,2- 
(Me2PhSiNH)2C6H4, 3, was deprotonated in situ and reacted with W(NPh)Cl4(OEt2) to 
yield W(NPh)Cl2(Me2PhSiN)2C6H4, 15. This compound was somewhat less soluble but 
recrystallization proved unfruitful. Yellow crystals of l,8-K2(Me3SiN)2CioH4, 16 or 1,8- 
Li2(Me3SiN)2CioH4, 17 were isolated when l,8-(Me3SiNH)2CioH4, 7, was 
deprotonated with two equivalents of KH or n-BuLi. These salts react readily with 
W(NPh)Cl 4 (OEt 2 ) to give W(NPh)Cl2(Me 3 SiN)CioH4, 18, as a dark powder which was 
markedly less soluble than 13, 14, or 15 eq 2.7. Nonetheless, a suitable solvent could 



23 

not be found for recrystallization. The same reaction using 4,5-dimethyl-l,2- 
(Me3SiNH)2C6H 2 , 6, yielded W(NPh)Cl 2 [4,5-Me2-l,2-(Me3SiN) 2 C 6 H2], 19. This 




Me 3 Si 




'K 



Me 3 Si 



Me 3 Si 



=\ 1 




N 
N N II ,.** C1 

-<: 

Cl 



Me3Si 



18 



eq2.7 



complex certainly simplified the *H NMR spectrum, but did not show any greater ease in 
isolation or crystallization. Attempts were made at synthesizing tungsten phenyl imido 
derivatives using the other ligands mentioned; however, although results were 
encouraging, full characterization of these derivatives was not obtained. 

It was also possible to substitute the chloride atoms in 14 with a more labile 
substituent. This was desirable if alkylation of the dichloride proved unsuccessful. When 
14 was allowed to react with two equivalents of AgOTf, the bistriflate complex, 
W(NPh)(OTf)2[(Me 3 SiN)2C6H4](OEt2), 20, was isolated as a bright orange powder. 
This complex must be more electron deficient than 14 since it forms an etherate complex, 
whereas 14 does not. 

Since all these compounds are five-coordinate, electron deficient molecules, they 
would be expected to form adducts with c-donor ligands. When PMe3 was added to a red 
Et 2 solution of 14, the solution immediately turned purple. Addition of pentane followed 
by slowly cooling the sample to -10 °C yielded dark purple crystals of 
W(NPh)Cl2(PMe3)[l,2-(Me3SiN) 2 C 6 H4], 21. Integration of the !H NMR and 
combustion analysis confirmed the stoichiometry of 21. Although 21 appears as a discreet 
mono-adduct, the 31 P NMR spectrum shows a very broad singlet for the PMe3 ligand, 
nearly 250 Hz wide, and suggests that at room temperature an equilibrium between 21 and 
free PMe3 was established. More evidence will be given for this ligand exchange later. 



24 



Purple, crystalline G-adduct complexes were also formed when 14 was exposed to THF, 
22; 3-picoline, 23; or CH3CN, 24, eq 2.9. Addition of these a-donors increases the 




+ L 



Me 3 Si 




eq2.9 



L = PMe 3 , 21; THF, 22; 3-picoline, 23; CH3CN, 24 



formal electron count of the molecules to 16e- with no 7t-donation from the folding of the 
ligand at this point. The donation of this electron density, as well as now having a 6- 
coordinate complex, would clearly have an impact on the ligand 'folding' which was 
observed in the structure of 14. Recrystallization of the PMe3 adduct, 21, by slowly 
cooling a pentane solution to -10 °C gave purple, x-ray quality crystals. 

The structure of 21, shown in Figure 2.9, has some unique features. Selected 
bond lengths and angles for the structure of 21 can be found in Table 2.2. The PMe3 
adds to the molecule trans to imido nitrogen, creating an octahedral geometry, with the 
amido nitrogens and the chlorides mutually cis in the basal plane. In a comparison between 
the structures of 14 and 21, one very general thing that stands out. Because of the added 
electron density and steric bulk of the PMe3, all the bonds to the metal center are longer in 
21. For instance, even the chlorides are 0.06 A or more further away. Most significandy, 
the fold angle has increased from 50 ° to only 28 °. The W-Qing distances have increased 
from 2.58 A each in 14 to 2.79 and 2.78 A in 21. It is interesting to note that the 
geometry around the nitrogen atoms in the bis-amide ligands in both 14 and 21 is virtually 
planar. The amide bond lengths in 21 are only slightly longer, 2.010(5) A and 1.990(5) A 
than in 14, 1.951(1 1) A and 1.952(1 1) A. One feature of this structure which is quite 



25 



Table 2.2: Selected Bond Lengths (A) and Angles (°) for compound 21. 

1-2 \-2 



Cll 


W 


C12 


2.449(2) 


92.43(7) 


Cll 


w 


P 




75.86(7) 


C12 


w 


P 


2.443(2) 


75.70(7) 


P 


w 


Nl 


2.720(2) 


87.2(2) 


P 


w 


N2 




89.2(2) 


P 


w 


N3 




160.3(2) 


Nl 


w 


N2 


2.010(5) 


80.8(2) 


N2 


w 


N3 


1.990(5) 


105.8(3) 


N3 


w 


CI 


1.747(6) 


124.6(2) 


CI 


w 


C2 


2.797(6) 


29.7(2) 


C2 


w 


Cll 


2.785(6) 


137.4(2) 


Nl 


Sil 




1.781(6) 




CI 


Nl 


W 


1.402(8) 


108.8(4) 


C2 


N2 


W 


1.387(9) 


109.8(5) 


C7 


N3 


W 


1.388(9) 


164.3(5) 



unusual is the extremely long W-P bond length, 2.720(2) A. This bond appears to be at 
least 0.2 A longer than most W-P bond lengths in W(VI) complexes. This weak 
interaction is supported by the afore mentioned broad singlet observed in the 31 P NMR 
spectrum. This long bond length may be due to trans influence of the imido nitrogen, 
which is a strong trans influencing ligand. 

A number of interesting new W(VI) imido and oxo complexes have now been 
prepared. These new complexes have interesting structural characteristics which will play 
an important role in influencing the chemistry associated with them. 



26 




g 
I 

O 



1-1 



P— \ 

Si 



Si 

P-i w 

9 p< 



cv£ 
•a c 

P,.>> 

£3 to 
o 

•a 



a 

u 



CHAPTER 3 
SYNTHESIS AND REACTIVITY OF W(VI) ALKYLS AND ALKYLIDENES 

3.1: Background Information on WP/D Alkyls and Alkvlidenes. 

In order to pursue the project goal of creating a new olefin metathesis catalyst, 
alkylation of the W(VI) dichloride was investigated. There are surprisingly few examples 
of group(VI) (fi alkyl complexes in the literature. 1 ' 2 - 42 ' 43 There are numerous examples of 
cfi group (IV) alkyl and dialkyl complexes, most of which are used as Ziegler-Naatta type 
catalysts. Homoleptic alkyls, such as WMe6 are well-known. 42 Other alkyls are less 
prevalent. Schrock has isolated a number of W(VI) imido alkyl complexes. 44 Many of 
these were isolated in attempts to find precursors for alkylidene complexes. It was 
observed that W(NPh)Cl2(CH2CMe3)2 was not isolable. However, if one or two of the 
chlorides are substituted with t-butoxide ligands, dialkyls can be isolated, W(NPh)Cl(0-f- 
Bu)(CH 2 CMe3)2 and W(NPh)(0-t-Bu) 2 (CH 2 CMe3)2. In these compounds, the alkyl 
groups are oriented cis to one another in a trigonal bipyramidal geometry. There are also 
examples in which the alkyl groups are trans to one another. Schrauzer prepared a variety 
of W(VI) dioxo complexes 45 of the type W(0)2R2(bipy), where R = Me, Et, n-Pr, and 
CH2CMe3. These compounds are quite stable due to the chelate effect of the bipyridine 
ligand, which also serves to lock' the alkyls trans to one another, limiting reductive 
elimination or a-hydrogen abstraction reactions. The bonding in d° alkyl complexes is 
rather straight-forward. The alkyl ligand acts as a 2e- donor ligand forming a G-bond with 
the metal center. The most common means of preparing alkyl compounds is by simple 
metathetical exchange reactions. 42 Grignard reagents and lithium, zinc, or aluminum alkyls 
are commonly used as alkylating agents. 



27 



28 

There are many possible reactions that can take place when a d° metal is alkylated, 
prohibiting isolation of a transition metal alkyl complex. If the alkyl group has (3-protons, 
the metal can undergo a (3-hydrogen elimination reaction. 2 ' 42 Another reaction that takes 
place, especially with bulky alkyl groups, is a-hydrogen abstraction. 2 An alkylidene is 
formed as a result. There are two mechanisms proposed for this reaction, neither of which 
has been proven. One is initial a-elimination to form an alkylidene-hydride complex. 
Evidence for this mechanism comes from the chemistry of later transition metals. This 
addition is not possible for a cP metal center because the reaction involves oxidation of the 
metal center. The other mechanism proposes a three-center, two-electron transition state 
which eliminates alkane, forming the alkylidene. Both cc-abstraction mechanisms can be 
seen in Figure 3.1. Since the discovery of the first alkylidene complex, other routes have 
been discovered for preparing alkylidenes. 46 

CH 2 R CHR CHR 

I ll/ H II 

M CH 2 R *- M ^ M +RCH3 (1) 

CH 2 R 



CH 2 R 



H 
R-C— --H , C ,HR 



/ 

^_CH 2 R M -f-K M +RCH 3 (2) 

R H 
Figure 3.1. The two a-abstraction mechanisms for alkylidene formation. 

Despite these developments, a-abstraction reactions are still the most common 
method for preparing alkylidene complexes. Neopentylidene (=CHCMe3) and 
neophylidene (=CHCMe2Ph) complexes are the most prevalent, due to their steric bulk and 
lack of (3-protons. Reactions that proceed through a-abstraction can be divided into two 
general categories, proximal a-abstraction and ligand induced a-abstraction a . Proximal a- 



a Proximal a-abstraction and ligand induced a-abstraction are not commonly used in the literature, however 
coining these terms is useful for the discussion. 



29 



abstraction refers to reactions in which an alkylidene is formed by oc-abstraction 
immediately upon alkylation. This type of reaction was observed for the addition of excess 
neopentyl grignard to TaCls, forming Ta(CHCMe3)(CH2CMe3)3. 13 The mere steric bulk 
of the neopentyl groups induces a-abstraction, eliminating neopentane. The second type of 
reaction, ligand induced a-abstraction, is characterized by the addition of a o-donor ligand, 
most commonly PMe3, to a cis bis-alkyl complex, inducing a-abstraction and elimination 
of an alkane. A classical example is the addition of PMe3 to 

W(NPh)(CH2CMe3)2(PMe3)Cl2, which results in the formation of the alkylidene complex 
W(NPh)(CHCMe3)(PMe3)2Cl2 and neopentane. 44 These principles will be discussed as 
they apply to the synthesis of the new alkylidene complexes that were synthesized during 
this study. 

3.2: Synthesis of WCVD Bis-Alkvl Complexes. 

Most of the reaction chemistry was performed on compound 14, since it was the 
first compound isolated and was available in large quantities. When 14 was allowed to 
react with two equivalents of ClMgCH2CMe3 in Et20 at -78 °C, the bis-alkyl complex 
W(NPh)(CH2CMe3)2[(Me3SiN) 2 C6H4], 25, was isolated as a dark red crystalline solid 
eq 3.1. The yield for this reaction was usually about 75-80%, and seems only to be 

P 

Me 3 Si T Me 3 Si 

x N x N 

V-VlU Et 2 rfWUv 




W^ + 2 eq. ClMgCH 2 CMe 3 ^ > (| I .W eq 3. 1 



1 1, / 

Me 3 Si 14 Me 3 Si 25 



limited by the extreme solubility of 25 in hydrocarbon solvents. There are many 
interesting characteristics of this compound. The l R NMR, shown in Figure 3.2, 



30 

showed that there was a plane of symmetry in the molecule. The neopentyl methyl groups 
were equivalent as were the -SiMe3 methyls. The methylene protons were observed as 
diastereotopic protons at 2.13 ppm and 2.29 ppm. The 2 Jh-H was 10 Hz, while there were 
183 W satellites observed at 1 1 Hz from 2 J\y-H- The aromatic region also shows the ligands 
protons resonating in an AA'BB' spin system, stemming from the symmetry plane in the 
molecule. These observations are consistent with the square pyramidal structure drawn in 
eq 3.1 for 25. Since 25 is only a 14e- complex (the degree of interaction of the metal 
center with the phenyl ring of the bis-amide ligand is not known, so an electron count of 
16e- might also be possible), and coordinatively unsaturated, an agostic interaction of one 
of the neopentyl methylene protons and the metal center is conceivable. It has been 
established that the magnitude of the coupling of the methylene proton with the methylene 
carbon is diagnostic of an agostic interaction. If the coupling constant is less than 120 Hz, 
then an agostic interaction is likely. 47 The 1 Jq-U f° r 25 was 123 Hz, and is consistent 
with a "normal" metal alkyl o-bond. An interesting point is that 25 was isolable as a cis 
(bis)-neopentyl complex. Recalling the structure of 14, the steric crowding around the 
metal center is overwhelming. It would seem likely that the bis-neopentyl complex would 
undergo a proximal a-hydrogen abstraction upon alkylation. The chelation of the bis- 
amido ligand may hinder the a-abstraction since rearrangement to a tetrahedral, four- 
coordinate alkylidene is necessary. 

Other bis alkyl complexes can be prepared in an analogous manner. The neophyl 
derivative W(NPh)(CH2CMe2Ph)2[(Me 3 SiN) 2 C6H4], 26, was isolated in 85% yield as a 
brownish powder which is less soluble in hydrocarbons than compound 25. For the case 
of the dimethyl derivative, W(NPh)(CH3)2[(Me3SiN)2C6H4], 27, isolation was more 
difficult. The compound was extremely soluble in pentane, and could only be isolated by 
cooling a concentrated solution of 27 in Et20 (1.2 grams in 2 ml) to -78° C, which gave a 
red solid after several days. The *H NMR spectrum of 27 is shown in Figure 3.3 and 
clearly shows the 3:1 ratio of -SiMe3 to W-Me2 peaks. Coupling of 183\y to the methyl 



31 



2 

a 

a 



w 



o 

_cu 



OJ 



in 
.01 



o 



in 



d 



~^> 



— ■* 



^ 



10 



U 



c4 
en 

3 



32 

protons was also observed and gives rise to the satellites of the methyl peak with 2 Jw-H = 6 
Hz. The ^C-H for 27 was 123 Hz as well, indicating that an agostic interaction is 
unlikely. When 14 was treated with two equivalents of CIMgEt, a red oil was isolated. 
The red oil appeared by NMR to be pure W(NPh)(CH 2 CH3)2[(Me3SiN) 2 C6H4], 28. The 
*H NMR spectrum revealed methylene resonances as multiplets at 1.91 and 2.31 ppm, 
while the ethyl-CH3 protons resonated as a singlet at 1.86 ppm. The ^c-H for 28 was 120 
Hz, consistent with the other bis-alkyls isolated. It was interesting that an electron deficient 
bis-alkyl complex with (3-protons was isolated. Often times these types of alkyls 
decompose by (3-hydrogen elimination making them difficult to isolate. The dibenzyl 
complex, W(NPh)(CH 2 Ph)2[(Me3SiN)2C6H4], 29, was prepared using benzyl grignard 
as the alkylating agent. The *H NMR was interesting because the benzyl methylene 
protons did not appear to be diastereotopic, as were the methylene protons in 25, 26 and 
28. The methylene protons resonated as a singlet at 2.78 ppm and integrate 2:9 to the 
-SiMe3 peak. However, when 29 was heated to 80 °C in C-jT>%, the resonance becomes 
what appeared to be a triplet. Cooling the sample only broadened the singlet. The 
methylene protons are considered diastereotopic, yet coincidentally have identical chemical 
shifts, obscuring any coupling. 

The synthesis of other bis-alkyl complexes has been investigated and show 
promise, although most of the products have not been completely characterized. Reacting 
two equivalents of allyl magnesium chloride with 14 gave a mixture of compounds. It 
appeared as though the major product was a bis-allyl complex where one allyl group was 
bound in an ri 1 manner while the other was T] 3 . More characterization is necessary to 
determine the identity of the compounds. The substitution of the chlorides on 14 with aryl 
groups was also investigated. A bright red powder was isolated when 14 is allowed to 
react with two equivalents of PhLi. The l H NMR confirmed the identity of the compound 
as W(NPh)Ph2[(Me3SiN)2C6H4], 30. This chemistry is currently being investigated by 
other members of the Boncella research group. Since the reactivity of 14 has shown so 



33 




.2 Z 



o t 



34 

much promise, alkylation of other dichloride derivatives was investigated. Allowing 
W(0)Cl2[(Me3SiN)2C6H4], 13, to react with two equivalents of neopentyl grignard does 
not afford isolation of the bis-neopentyl complex as expected. However, the l H NMR 
spectrum of the brown solid shows resonances similar to the diastereotopic methylene 
protons of 25. This result was not unexpected since the chemistry of the oxo complex was 
consistently less clean than the imido compounds. A similar result was observed when 
W(NPh)Cl2(Me3SiN)2CioH4, 18, was allowed to react with neopentyl grignard. Full 
characterization was not achieved but the spectral data were consistent with a bis-neopentyl 
complex. Better results were achieved when W(NPh)Cl2(Me2PhSiN)2C6H4, 15, and 
W(NPh)Cl2[4,5-Me2-l,2-(Me3SiN)2C6H2], 19, were allowed to react with neopentyl 
grignard. The two new bis-neopentyl complexes, 

W(NPh)(CH2CMe3)2(Me2PhSiN) 2 C6H4, 31 and W(NPh)(CH 2 CMe3)2[4,5-Me2-l,2- 
(Me3SiN)2CgH2]» 32, were isolated as dark red solids and have spectral properties that are 
similar to 25. 

Heretofore, only bis-alkyl or bis-aryl compounds were isolated. However, adding 
only one equivalent of alkyl to the metal center should also be possible. When one 
equivalent of neopentyl grignard was allowed to react with 14, the mono-neopentyl 
chloride complex W(NPh)Cl(CH2CMe3)(Me 3 SiN)2C6H4, 33 was isolated as a red 
powder eq 3.2. The methylene protons of the neopentyl groups were observed as 



Me 3 Si 

x N 

\ La 




W + 1 eq. ClMgCH 2 CMe 3 

. / X n -78 °C \^ / \ ri eq3.2 

N CI 

Me 3 Si 14 

diastereotopic doublets at 1.93 and 2.08 ppm respectively ( 2 Jh-H = 10 Hz). The ] H NMR 

spectrum of the mono-neopentyl complex, 33, differs from the bis-alkyls due to the 




35 

absence of a plane of symmetry. The -SiMe3 resonances were observed as inequivalent 
singlets, whereas they were equivalent in the bis alkyl complexes. In the aryl region, an 
AA'BB' spin system was no longer observed for the bis-amide ligand, each ligand aryl 
proton was inequivalent (two doublets and two triplets). 

There are few examples of mixed alkyl complexes, so 33 would be a prime 
candidate to allow asymmetric substitution. When 33 was allowed to react with one 
equivalent of MeLi in an NMR tube, W(NPh)(CH 3 )(CH2CMe 3 )(Me3SiN)2C6H4 was 
generated. The *H NMR showed four singlets in the alkyl region, in a 3:3:3: 1 ratio, 
corresponding to the two-SiMe3 groups, the neopentyl group, and the methyl group. 
Diastereotopic methylene protons are also observed. This compound was not isolated on a 
preparatory scale. Another asymmetric compound was isolated when 33 was allowed to 
react with one equivalent of LiNMe2, forming 
W(NPh)(CH 2 CMe3)(NMe2)(Me3SiN)2C 6 H 4 , 34, eq 3.3. 



N 



Me 3 Si 

W 
N 
Me3Si 33 




a 



+ LiNMe2 



Me 3 Si 

XT N / 

w 




N 



/ 



Me 3 Si 



34 



N- 

I 

Me 



eq3.3 



The *H NMR spectrum of 34 reveals diastereotopic methylene protons as doublets at 1.33 
and 2.60 ppm respectively. There is lack of rotation about the W-NMe 2 bond, since two 
singlets were observed at 3.19 and 3.68 ppm. This lack of rotation is due to the n- 
donation of the lone pair of electrons on the amide nitrogen to the metal center. This type 
of interaction is quite common in electron deficient molecules such as 34. Taking into 
account the electronic donation from the bis-amide ligand, this molecule should be 
considered as being electronically saturated. 



36 



3.3: Alkylidene Formation From Bis-Alkvl Complexes. 

In Section 3.1, the two mechanisms of alkylidene formation from bis-alkyl 
complexes were discussed. The fact that bis-alkyl complexes were isolated does not 
eliminate proximal a-abstraction as a route to alkylidene formation. Without adding a o- 
donor ligand, a-abstraction could be thermally induced. Although there are no examples of 
thermally induced a-abstraction reactions, this route should be viable. Many proximal a- 
abstraction reactions are performed at reduced temperatures, and warmed to room 
temperatures where a-abstraction takes place. Since the bis-alkyl complexes are thought to 
exist at low temperatures in these reactions, a-abstraction occurs at or near room 
temperature. Heating a C^De solution of 25 in a sealed NMR tube gave a very interesting 
result. Neopentane formation was observed in the l H NMR, however, it was not a result 
of a-hydrogen abstraction. The *H NMR spectrum reveals what appears to be a 
metallacyclobutane complex formed from the y-abstraction of a proton from a neopentyl 
methyl group eq. 3.4. The 2 H NMR spectrum of the p\p*-dimethylmetallacyclobutane 
complex, W(NPh)(CH2CMe2CH2)(Me 3 SiN)2C6H4, 35, is consistent with other 

3 



Me 3 Si^ T Me 3 Si 

/yvJ/-4 80 o C rrVVJV* 

KJ^^ \ / 2-3 days 

Me 3 Si 25 



f 




+ CMe 4 eq3.4 



metallacyclobutane complexes in the literature. 48 There are two doublets, at -1.7 and 2.1 
ppm respectively ( 2 Jh-H = 9 Hz), corresponding to the methylene protons of the 
metallacycle. The large difference in chemical shift of the protons is consistent with other 
metallacycles. 48 The methyl protons of the metallacycle resonated at 0.54 and 0.57 ppm 
respectively. They were inequivalent since they lie above and below the plane of the 



37 

metallacycle. This compound has not been fully characterized since it was difficult to 
isolate and purify. The difficulty in isolating the metallacycle results from the 2-3 days of 
heating which were required for the complete thermolysis of 25 to 35. During this time, 
metallacycle formed earlier in the reaction started to decompose to unidentifiable products. 
However, 35 is formed by other routes and will be discussed at length later in Chapter 
Four. It seems unusual that 25 would undergo a y-abstraction, however there are 
examples of this type of reaction in the literature. For example, Marks 49 thermally 
decomposes Cp*2Th(CH 2 CMe3)2 and observes the loss of neopentane, giving the p,(3'- 
dimethylcyclobutane thorium complex, Cp*2Th(CH2C(Me)2CH2). 

Further investigation into this reaction using other bis-alkyls proved to be 
unfruitful. The bis-neophyl complex, 26, was interesting since it possesses at least three 
thermal decomposition routes that involve proton abstraction reactions. These include: a- 
hydrogen abstraction, forming a neophylidene; y-abstraction similar to 25 to give a |3- 
methyl, fi'-phenyl metallacyclobutane; or orr/zo-metallation, forming a five-membered 
metallacycle. Examples of each of these types of reactions have been reported in the 
literature. The a-abstraction and y-abstraction reactions have already been discussed. 
Orthometallation reactions are observed for compounds in which the abstraction of a proton 
from the ortho position of an aryl group forms a five-membered ring. 2 - 50 A good example 
is the thermolysis of CH 3 Rh(PPh 3 )3, shown in Figure 3.4, in which the ortho proton of 

Ph 



[(C 6 H 5 )P] 3 RhCH 



\ 

p,^ P. ,Rh[P(C 6 H 5 )3] 2 




-CH 4 
Figure 3.4. Orthometallation of (Ph3P)3RhMe 

one of the phenyl groups is abstracted, releasing methane and forming a metallacycle. 51 
However, when 26 was thermally decomposed at 90 °C for 3 days, no discernible 
products were observed. Interestingly, the P-methyl, p'-phenyl-metallacyclobutane 



38 

complex will be isolated and discussed by an alternate route in Chapter 4. Similarly, only 
complete decomposition to indiscernible products was observed when the dibenzyl and 
diethyl compounds were heated. The dimethyl complex was unique in that it was thermally 
stable over a period of 10 days at 90 °C. 

Since no thermal pathways seemed to lead to alkylidene formation, ligand-induced 
a-abstraction was attempted. In a sealable NMR tube, one equivalent of PMe3 was added 
to a C<5D6 solution of the bis-neopentyl complex, 25. Over a period of ten days at room 
temperature, no reaction was observed by *H NMR. Interestingly enough, no peak shifts 
were observed corresponding to coordination of PMe3. Even upon cooling a C7D8 
solution of 25 and PMe3 gives no evidence of ligand coordination by observation of the l H 
NMR. This behavior was contradictory to the behavior of the dichloride precursor, 14, 
which forms adducts with o-donors quite readily. The bis-neopentyl complex, 25, is 
isoelectronic with 14, but the steric environment at the metal center in 25 would obviously 
be much more hindered. The tube was then warmed to 70 °C in an oil bath. After only 
three hours, neopentane formation was observed by *H NMR. Additionally, a doublet 
began to grow in at 9.62 ppm, indicative of an alkylidene proton coupled to a bound 
phosphine. The reaction proceeded nearly to completion at this temperature in 3 days; 
however, it was found that the reaction proceeds faster and much cleaner with two or three 
equivalents of phosphine present and a temperature of ca. 90 °C, eq 3.5. 



Me 3 Si x I Me 3 Si H x ^X 

, N \ N PMe 3 

Me 3 Si 25 Me3S / 36 

In order to prepare and characterize this new alkylidene on a preparatory scale, a problem 
had to be overcome. In an open system, PMe 3 , which has a high vapor pressure and boils 




39 

at 39 °C, would be lost when the reaction was heated to 90 °C. Additionally, heating a 
solution in a closed system using conventional Schlenkware would be dangerous due to a 
possible buildup of pressure. This problem was overcome by dissolving 25 in toluene in a 
tube fitted with a Young's joint with a Teflon seal. Three equivalents of PMe3 were added 
and the reaction was heated to 90 °C for 12 hours. The color of the solution changed from 
dark green to bright orange over the time of the reaction. After cooling to room 
temperature, the solution was transferred to a Schlenk flask where the solvent was 
removed. Extracting with pentane and cooling to -10 ° C gave orange crystals of the new 
alkylidene complex, W(NPh)(CHCMe3)(PMe3)[(Me 3 SiN)2C6H4], 36. 

In the ! H NMR of 36, a doublet was observed at 9.62 ppm ( 3 J P . H = 4 Hz) 
corresponding to the alkylidene proton. Tungsten satellites were also observed for this 
resonance ( 2 Jw-H = 1 1 Hz). The alkylidene carbon was observed at 277.4 ppm ( l Jc-Ha = 
1 10 Hz). This coupling is consistent with an agostic interaction between the alkylidene 
proton and the metal center. The PMe3 resonance was observed as a doublet at 0.98 ppm 
( ! Jp-H = 9 Hz) in the *H NMR spectrum. There are three other singlets in the alkyl region 
of the 2 H NMR spectrum of 36, all in a 1: 1 : 1 ratio. One is the neopentyl methyl group, 
1.39 ppm, while the other two are the silyl methyl groups, 0.38 and 0.41 ppm. The 
aromatic region also confirms that the molecule no longer has a plane of symmetry which 
would make the silyl methyls equivalent. 

The geometry of the five-coordinate alkylidene complex, 36, cannot be deduced 
merely from the spectroscopic data. Since this was a five-coordinate complex, there were 
numerous square pyramidal and trigonal bipyramidal complexes which would have fit the 
spectral data. Therefore determination of the crystallographic structure was essential, not 
only to determine the geometry of the molecule, but also to gain insight into the catalytic 
activity of the molecule which will be discussed later in this chapter. Slowly cooling a 
pentane solution of 36 to -10 °C afforded single orange crystals which were suitable for 
diffraction. 



40 

The thermal ellipsoid plot of 36 is shown in Figure 3.5. Selected bond lengths 
and angles can be found in Table 3.1. Upon examining other group (VI) alkylidene 
complexes, 8 it was found that the structure of 36 was very unique. The geometry was 
square planar with the alkylidene in the apical position. The tungsten atom lies 0.61 A 
above the square plane defined by the imido nitrogen, the PMe3 phosphorous atom, and the 
two amide nitrogens. The average deviation of Nl, N2, N3, and PI from the square plane 
was only 0.03 A. Re-examining the issue of the interaction between metal center and the 
7t-system of the bis-amide ligand gives an expected result. Since the electron count of the 
molecule has been increased by two by the addition of the ligand, a decrease in the fold- 
angle would be expected. The fold angle was 40 °, a 10 ° increase from the dichloride 
structure, 14, yet 12 ° less than the fold angle in the six-coordinate PMe3 adduct of the 
dichloride, 21. The 40 ° fold angle suggests a weak interaction between the aryl ring of the 
bis-amide ligand and the metal center. The angle may be due, in part, to the great steric 
bulk around the metal center. Thus, the folding of the bis-amide ligand may be necessary 
to relieve steric interactions. 

It was apparent that the chelating nature of the ligand has dictated the observed 
geometry of the molecule. The literature reveals that five-coordinate imido-alkylidene 
complexes of tungsten and molybdenum prefer to adopt trigonal bipyramidal, rather than 
square pyramidal structures. The compounds, ann'-W(fra«.y-CHCH=CHMe)[N-2,6- 
C6H 3 e'Pr)2](OCMe(CF3) 2 ]2(quinuclidine) 52 and W(CHCH=CHPh 2 )[N-2,6- 
C6H 3 ('Pr)2](OCMe(CF3)2]2[P(OMe)3]53 are good examples of the preferred trigonal 
bipyramidal structure of these types of compounds Figure 3.6. Although 36 and these 
two alkylidenes have similar substituents, the geometry's are much different. The 
geometric constraints of the chelating bis-amide ligand must be responsible for the 



41 



c 
o 



ft 

H 




42 



Table 3.1: Bond Lengths (A) and Angles (°) for the non-H atoms of compound 36. 



1-2 1-2-3 



P1 W Nl 2.502(4) 82.8(4) 

PI W N2 148.13 

PI W N3 81.2(3 

Nl W N2 1.789(9) 98.4(4) 

Nl W N3 140.14 

Nl W C13 103.6(5 

N2 W N3 2.095(10) 77.8(4) 

N2 W C13 H3.0(5) 

N3 W C13 2.067(10) 114.6(4) 

N2 Si2 C18 1.736(11) 108.6(6) 

N3 Si3 C21 1.761(9) 111.8(6) 

C1 Nl W 1.387(14) 160.8(9) 

C7 N2 W 1.39(2) 106.6(8) 

W N2 Si2 129.8(5) 

C12 N3 W 1.40(2) 105.6(7) 

C8 C7 N2 128.613) 

C12 C7 N2 1.43(2) 114.6(11) 

C14 C13 W 1.50(2) 148.4(9) 

C13 W PI 1.884(13) 97.5(4) 



unique geometry of 36. The bis-amide ligand of 36 should be able to coordinate in a axial- 
equatorial ligation, allowing the molecule to adopt a trigonal bipyramidal geometry, but it is 
not observed. 



T N 
"Pr ' 

RO' 



Pr 1 t* ss v- Pl ' i 



>=< >Pr N ^; » 

Ph / 

RO 

P(OMe) 3 



>h Me 





Figure 3.6. Examples of trigonal bipyramidal alkylidenes. 

Although the solid state structure of the compound has been solved, the structure in 
solution was actually the key to the reactivity of the molecule. When the alkylidene proton 
was irradiated in an nOe experiment, a 6% enhancement was observed for both the silyl 



43 

methyl groups. No significant enhancement was observed for the imido aryl protons, or 
the PMe3 methyls. When the neopentyl methyls were irradiated, the ortho-aryftrmdo 
protons and the PMe3 protons where enhanced by 2.5% and 3.7% respectively, while no 
significant enhancement was observed for the silyl methyl groups. This geometry will be 
referred to as syn, where the neopentylidene r-butyl group is syn to the imido group. 

There are two reactions which should be considered at this time to better understand 
the role of the PMe3 in the formation of the alkylidene. First when Cu(I)Cl was added to a 
C6D6 solution of the alkylidene, 36, formation of the metallacyclobutane complex, 35, 
was observed by ! H NMR eq 3.6. Cu(I)Cl forms an insoluble adduct with PMe3 and 
effectively removes it from the solution. The four-coordinate alkylidene then undergoes a 
rearrangement to the metallacycle. The rearrangement is effectively a 1,3 shift of a proton 



^ Jf*. II ^^^ \ T N 



^/^ +Cu(I)C1 ^^ (J N /\A +CuC1(PMe3) * eq36 

M63Si/ 36 Me 3 Si /N 35 

from a y-methyl to the alkyhdene carbon, as well as forming the new W-C bond. Although 
the nature of this rearrangement is not known, the result is undeniable and will be 
discussed further in Chapter 4. Secondly, when PMe3 was added to a CgDg solution of the 
metallacycle, 35, complete conversion to the alkylidene, 36, was observed by !H NMR 
eq 3.7. These two reactions show the relationship between the alkylidene, 36, and the 
metallacycle, 35. 

Insight into the mechanism by which the alkylidene, 36, is formed from the bis- 
neopentyl complex, 25, eq 3.5, is gained by these reactions. The thermolysis of 25 in 
the absence of PMe3 might initially give a four-coordinate alkylidene, which quickly 
rearranges to give the five-coordinate metallacycle, 35. In the presence of PMe3, the four- 
coordinate alkylidene is 'trapped' by the phosphine, forming 36. The intermediate four- 



44 



Me 3 Si 




N. 



N 



VJI/^ 



w; 



N 



X 




Me 3 Si 



./ 



35 



+ PMe 3 



C 6 D 6 



Me 3 S 



\ H v^ 



N,. 




N PMe 3 

Me 3 Si 36 



eq3.7 



coordinate alkylidene could be tetrahedral, and coordination of the PMe3 would result in 
rearrangement to the observed geometry of 36, with the alkylidene in the apical position. 
This mechanism can be seen in Figure 3.7. Regardless of the actual mechanism, the 
observed net result was still a-abstraction induced by PMe3. 



P 

Si. T 



Me 3 Si 25 



<■ 



Me 3 Si 





W- 



<^n' 



Me 3 S 



3 M 






H 




Me3Si 



PMe 3 



Me 3 S 




/ \ 

PMe 3 



/ 



Me 3 Si 



36 



Figure 3.7. Scheme for alkylidene and metaUacycle formation 
showing an intermediate tetrahedral alkylidene. 



Although the application of the PMe3 ligand to induce an a-abstraction reaction 
might be widely applied to the other bis-alkyl compounds isolated, the bis-neopentyl 
appears to be a unique case. The neophylidene compound can be isolated, however, a 



45 

longer reaction time is necessary. When the dimethyl complex, 27, was heated to 90 °C in 
the presence of excess PMe3, no reaction was observed over 10 days, not even 
decompostion of the dimethyl complex. Once again, it was astonishing that no PMe3 
adduct formation was observed. Adduct formation would be expected since the methyl 
substituents are not much bigger than the chlorides in 14. When the diethyl complex, 28, 
was heated to 90 ° C with PMe3, decomposition to indistinguishable products was 
observed. Surprisingly, when the dibenzyl complex, 29, was heated with excess PMe3 
the compound appeared quite stable. No benzylidene formation was observed over time in 
the l H NMR, although after a week at 90 °C, decomposition occurred. Though 
disheartening, it is not uncommon to see a unique behavior when dealing with neopentyl 
and neophyl compounds. The first as well as the most common examples of alkylidenes 
are either neopentyl or neophyl. 

The nature of the a-donor ligand necessary to induce a-abstraction was also 
investigated. It would be advantageous to be able to prepare alkylidenes from the bis- 
neopentyl compound using the weakest a-donors available. This would facilitate easy 
removal of them either to isolate a four-coordinate alkylidene or the in situ dissociation of 
the ligand forming a transient four-coordinate intermediate. When the bis-neopentyl 
complex, 25, was heated in the presence of PEt3 in a sealable NMR tube, the alkylidene 
complex W(NPh)(CHCMe3)(PEt3)[(Me 3 SiN)2C6H4], 37, was observed. However, 
when trying to isolate 37 on a preparatory scale, a mixture of the alkylidene and the 
metallacyclobutane complex was isolated. The lack of phosphorous coupling to the 
alkylidene proton in the l H NMR of 37, which was observed as a broad singlet at 9.82 
ppm, was evidence of the weak coordination of the PEt3 ligand. Weak coordination was 
also evident from the 31 P NMR spectrum. The PEt3 was observed as a broad singlet at 
-1 1.42 ppm; no 183 W satellites were observed as was the case with the PMe3 adduct of the 
alkylidene. As expected, when PMe3 was added to a C^ solution of 37, immediate 
formation of the PMe3 adduct, 36, was observed by ! H NMR. Using other phosphines 



46 

did not lead to the isolation of new alkylidenes, only decomposition or formation of the 
metallacyclobutane complex was observed by *H NMR. These reactions were attempted 
using PMePh2, PCy3, and PPh3. When quinuclidine, N(CH2CH2)3CH, was heated in a 
C6E>6 solution of the bis-neopentyl product, the metallacycle was the only product 
observed. This was curious since quinuclidine serves as a a-donor for other electron 
deficient organometallic compounds, including a number of alkylidenes. 52 Only 
decomposition was observed when THF or DME were utilized as the a-donor ligands. 

One property of the new alkylidene which was promising was the thermal stability 
of the molecule. A NMR tube containing a C7D8 solution of the PMe3 adduct, 36, can be 
heated to 90 °C over days with no observed decomposition in the l H NMR spectrum. 
Even though more alkylidenes could not be prepared, the isolation of this new alkylidene 
offers a starting point for a study into the metathesis activity of this chelated alkylidene. 
Although it would have been desirable to be able to prepare more derivatives of alkylidenes 
using this new o-phenylenediamine ligand system it is not unusual to see this type of 
reactivity. The formation of alkylidenes by means of a-abstraction of an alkyl proton is a 
delicate reaction. There are many factors which influence the reaction products. The 
sterics of the ancillary ligands and bis alkyl groups play important roles, as well as the 
electronics of the ancillary ligands. These factors play important roles not only in the a- 
abstraction reaction, but also in the stability of the alkylidene itself. There are many 
decomposition pathways available for alkylidenes, and the balance of steric and electronic 
factors of all the substituents must be carefully controlled for isolation of a stable 
alkylidene. 54 

3.4. Metathesis activity of WfNPh^CHCMe^HPMe^rfMe^SiNbC^ H^l. 36. 

Before examining the metathesis reactivity of the alkylidene, the mechanism of this 
reaction should be considered as well as how it applies to the known structure of 36. 



47 

Schrock has done extensive studies 8 which have concluded that in olefin metathesis 
reactions the olefin prefers to attack the C-N-0 face in the alkoxide alkylidenes. This 
would translate to the C-Ni m ido-N a mido face in the chelated alkylidene. The open 
coordination site in 36 is trans to the alkylidene carbon, where, if the olefin coordinated, 
rearrangement of a six-coordinate complex would be necessary. The most likely 
mechanism for olefin metathesis with this new alkylidene involves prior dissociation of the 
PMe3 ligand, followed by attack of the olefin on the vacant coordination site at the C- 
Nimido-Namido face of the molecule. Support for this mechanism will be offered 
throughout the discussion. 

When a pentane solution of W(NPh)(CHCMe3)(PMe3)[(Me3SiN)2C6H4], 36, was 
refluxed with one equivalent of diphenylacetylene, a metallacyclobutene complex, 
W(NPh)[C(H)(r-Bu)C(Ph)C(Ph)][(Me 3 SiN)2C6H4], 38, was isolated as a red oil eq 3.8. 
In the ! H NMR spectrum a singlet was observed at 2.82 ppm (J 2 w-H = 8 Hz) 



Me 3 S 



i K X 




> X R .A 1 



N PMe 3 ph 

Me 3 Si 36 




Ph eq3.8 



corresponding to the oc-proton of the metallacyclobutene complex. Metallacyclobutene 
complexes of tungsten are quite common, arising from the metathesis of alkylidenes with 
diphenylacetylene. 55 Although the reaction took place under relatively mild conditions by 
heating to 35 °C, it is important to note that the reaction must be carried out in an open 
system. A different result is observed if the phosphine is not liberated from the reaction 
mixture. In a sealable NMR tube, a C6D6 solution of 36 and diphenylacetylene was 
warmed to 50 °C for 3 days. The l U NMR reveals the formation of 38 within 10 hours, 
however, after 3 days, a singlet was apparent at 5.50 ppm, as well as a much smaller 



48 

singlet at 5.45 ppm. A broad singlet was observed at 0.90 ppm, presumably a new PMe3 
resonance. The new product was apparently a vinyl alkylidene, arising from the PMe3 
induced ring opening of the metallacycle, eq 3.9. 



Me 3 Si Yh L^ Me 3 Si Y 

?X~ x N PMe 3 

PMe 3 ff'V *"'4K P1 \ eq3.9 




W 



H 




50 °C V^v / 

N 

/ Ph 

Me 3 Si 



The observation of two new olefinic resonances was most likely due to formation of both 
cis and trans isomers of the vinyl alkylidene. This reaction has been observed for other 
metallacyclobutene complexes when a-donor ligands are added. 55 

The ring opening metathesis polymerization (ROMP) of norbornene, NBE, was 
chosen in order to investigate the olefin metathesis activity of 36. The alkylidene, 36, 
polymerized 25 equivalents of NBE in 10 minutes. Analysis of the polymer using GPC 
techniques reveals a very high molecular weight for the polynorbornene. The molecular 
weight was determined to be 61,000 g/mol versus a polystyrene standard. However, 
Schrock and Grubbs have determined that a conversion factor of 2.2 is appropriate for 
polynorbornene versus polystyrene. 17 This would make the corrected M n = 27,000 g/mol. 
This was still enormous compared to the molecular weight which would be expected if all 
the catalyst was active. If 100% of the catalyst was initiated and propagating, the molecular 
weight should be near 2500 g/mol. This result showed that less than 10% of the catalyst 
was active. This result was consistent with the prediction that phosphine must be lost in 
order for the olefin to coordinate to the metal center. Also, in order to observe such a high 
molecular weight, the rate of the propagation step must be much faster than the rate of the 
initiation step. Figure 3.8 demonstrates this as well as the dependence the reaction would 
have on the presence of PMe3 in the reaction mixture. 



49 

Grubbs studied the effect PMe3 had on the ROMP of cyclobutene 56 by Schrock's 
catalyst, W(NAr)(CH-t-Bu)(0-t-Bu)2, Ar = 2,6-diisopropylphenyl. The observations 
made by Grabbs were consistent with the ROMP of NBE by the catalyst, 36. In order to 
observe the effect of added PMe3, 36 was dissolved in toluene in the presence of ten 
equivalents of PMe3. A toluene solution of 150 equivalents of NBE was then added and 
the mixture was stirred for one hour. Precipitation with methanol gave a 80% yield of 
polynorbornene. The lack of consumption of the monomer, even over the longer reaction 
time, demonstrates the effect of PMe3 on the rate of the reaction. Analysis of the polymer 
using GPC techniques versus a polystyrene standard gave a corrected M n = 35,000 g/mol. 
The theoretical M n , 14,124 g/mol, was roughly 50% of the observed M n , compared to less 



WF^ ^=f W=^ +™e3 (1) 

PMe 3 A B 



X + JK _^ [Wr =-O^Y 



B C 

[W^O^ + PM03 ^ ^V^O^ 

k-3 I 
C PMe 3 D 



(3) 



Figure 3.8. Kinetic scheme for the polymerization of norbornene by 36. 

than 10% for the uninhibited polymerization reactions. All of the GPC data for the NBE 
polymerization reactions can be found in Table 3.2. The percentage of active catalyst has 
been increased dramatically by the addition of PMe3. It is important to note how the 
phosphine is affecting the polymerization. The added PMe3 must be hindering propagation 
to a much greater extent than it is hindering initiation. Grubbs measured the Keq of PMe3 



50 

binding to both the uninitiated catalyst, A, and the propagating alkylidene, D. 56 It was 
observed that the PMe3 binds much more strongly to the propagating alkylidene than the 
uninitiated catalyst. This large difference in binding energy virtually stalls the propagation 
of the polynorbornene, allowing much more alkylidene to initiate. For the polymerization 
of NBE using 36 as the catalyst in the presence of PMe3, the reaction was slowed to such 
an extent that after an hour, the reaction only reached 80% completion. But, judging from 
the M n of the polynorbene polymers formed, the percentage of active catalyst was still well 
below 100%. 

The percentage of active catalyst was normally observed to be between 40% and 
60% when ten equivalents of PMe3 were used. So, in the inhibited polymerization of NBE 
using 36, although the added phosphine makes k? » k_i, k-i was still much larger than 
ki. If k_i > ki, then the observed percentage of active catalyst was understandable. At 
room temperature, an equilibrium was observed between A and B for Grubbs' system, 
with the equihbrium favoring B. 56 At room temperature, no equilibrium was observed for 
36, the PMe3 was tightly bound with distinctive 183 W satellites (^w-P = 128 Hz). 

The nature of the propagating alkylidene was also observed in an NMR tube 
reaction. Five equivalents of PMe3 and five equivalents of NBE were allowed to react with 
36 in C6D6. After one hour the l B. NMR spectrum of the reaction revealed that only 80% 
of the NBE was consumed. Also, ca. 40% of 36 was converted into propagating 
alkylidene. Two broad resonances were observed at 9.09 and 9.31 ppm. These peaks 
correspond to the syn and anti isomers of the propagating alkylidene species. 17 ' 56 

One property that was not mentioned about the poly(norbomene) polymers 
catalyzed by 36 was the molecular weight distribution. The polydispersity index, PDI, is a 
measure of distribution of the molecular weight of the polymer chains and is calculated by 
M w /M n where M w is the weight-averaged molecular weight and M n is the number-average 
molecular weight. All of the polymers which were prepared displayed very narrow 
polydispersities, regardless of whether or not the polymerizations were inhibited by PMe3. 



51 

A comprehensive theoretical study was done by Gold 57 in order to understand the 
relationship between the observed PDI values and the relative rates of propagation and 
initiation, kp/ki. This study, simplified by others, 58 allows a determination of the 
theoretical M w /M n based on kp/ki. The formula takes into account the initial concentrations 
of catalyst and monomer, and the concentrations of catalyst and monomer at any given 
time. 

From NMR experiments, after 30 minutes the uninhibited NBE polymerization has 
10% active catalyst with 40% of the monomer consumed. This gives a relative kp/ki of 
115. This was extremely fast although the high molecular weights observed agree with this 
calculation. In a similar experiment inhibited by 5 equivalents of PMe3, the relative kp/ki 
was observed to be 30. The effect of the PMe3 can be seen on the relative rate, however, a 
kp/ki of less than 1 would serve to initiate all the catalyst and give better control of the 
molecular weight of the polymerization. From Gold's calculations, 57 relative kp/ki's of 
this magnitude should give PDI values between 1.005 and 1.12. 

Table 3.2. Polymerization of NBE using 36, inhibited vs. uninhibited. 
Inhibited with 10 equivalents of PMe3 



eq's of NBE 


time 


150 


lhr 


1000 


lhr 


163 


3 hrs 


70 


4hrs 


25 


5 min 


100 b 


5 min 


342 


10 min 


52 


lhr 



Mn/ corrected 3 


PDI 


Mn/ theoretical 


% vield 


35,000 g/mol 


1.01 


14,124 g/mol 


80 


104,000 g/mol 


1.00 


94,217 g/mol 


65 


94,000 g/mol 


1.07 


15,357 g/mol 


85 


126,000 g/mol 


1.07 


6,592 g/mol 


88 


Uninhibited 








28,000 g/mol 


1.12 


2,354 g/mol 


90 


37,000 g/mol 


1.07 


9,517 g/mol 


90 


120,000 g/mol 


1.03 


32,202 g/mol 


90 


115,000 g/mol 


1.04 


4,888 g/mol 


95 



a. A correction factor of 2.2 was applied for polynorbornene vs. polystyrene. 

b. The polymer was end-capped with benzaldehyde after 5 minutes. 



52 

The catalytic reactivity of 36 has been examined for other systems as well. The 
alkylidene, 36, catalyzes the polymerization of cyclooctene, however, only at elevated 
temperatures. This supports the mechanism of dissociation of PMe3 before the olefin can 
attack. The ROMP of cyclooctene has a higher activation barrier than NBE since there was 
much less ring strain to be relieved and the NBE is much smaller, allowing NBE monomer 
to coordinate more readily to an open coordination site of the catalyst. The ADMET 
polymerization of 1,9 decadiene has also been investigated. It was already discussed that 
36 is stable to thermal decomposition in refluxing toluene, therefore, it should be a 
candidate for a thermally stable ADMET catalyst. Observations did not agree with this 
assertion. The alkylidene does catalyze the ADMET oligomerization of 1,9-decadiene, 
however, the reaction never proceeded past dimers and trimers. It has been suggested that 
36 has a preference for internal olefins, causing unproductive metathesis, however this or 
any other explanation has not been substantiated. 

One aspect of the ADMET reaction which was observed was the poisoning of the 
catalyst by the ethylene produced in the reaction. When ethylene was bubbled into a CyD6 
solution of 36, the J H NMR initially reveals what appears to be a metallacyclobutane 
complex with an cc-t-butyl group. There were multiplets at 2.40 ppm, 2.62 ppm, and 3.76 
ppm in a 1:1:1 ratio. A new singlet at 1.20 was also observed in a 9:1 ratio with the 
singlets. Over time these resonances diminished as resonances grew in which correspond 
to a unsubstituted metallacyclobutane complex. The l H NMR reveals multiplets at 1.80 
ppm, 1.91 ppm, 2.20 ppm, 2.58 ppm and 2.75 ppm in a 1:1:1:2:1 ratio. Figure 3.9 
shows the scheme by which the a-t-butyl metallacyclobutane is formed and then further 
reacts to give the unsubstituted metallacyclobutane complex. Although there was no other 
spectral data to support this mechanism, this appears analogous to the behavior displayed 
by Schrock's catalyst. 48 ' 59 The peak positions of both metallacycles correspond to 
observations made for the alkylidene, W(NAr)(CH-t-Bu)(OR)2 and ethylene. 59 
Examination of the room temperature l H NMR over the course of the reaction did not 



53 



reveal the intermediate methylidene complex, which must be formed before the 
unsubstituted metallacycle can be formed. 



[W] 
t 



PMe 3 



[W] 



X 



>! 





[W] 
t 



-CMe 4 
+ PMe 3 



H 



- PMe 3 j ^H 

PMe 3 

Figure 3.9. Proposed mechanism for formation of an unsubstituted 
metallacycle from the reaction of 36 and excess ethylene. 



Recently, the applications of ADMET have been expanded to the depolymerization 
of unsaturated polymers. Wagener has utilized Schrock's catalyst in order to depolymerize 
1,4-polybutadiene, end-capped with a silylene. 60 Although 36 proved unsuccessful for 
the polymerization of 1,9-decadiene, possibly because of a preference for internal olefins, 
its activity as a depolymerization catalyst was investigated. 500 equivalents of 1,4- 
polybutadiene was dissolved in minimal toluene in the presence of 36. After 24 hours, 
500 equivalents of the end-capping group were added. GPC analysis revealed that the 
depolymerization was successful. Only monomer and dimer were present. Currently, 
further work is being done on this reaction. 

In this chapter, the substitution of the chlorides in 14 led to the isolation of 
numerous new alkyl complexes. The chemistry of the bis-neopentyl derivative, 25, led to 
the isolation of a new metallacycle and new alkylidene complex. The metathesis reactivity 
of the alkylidene, 36, was investigated and shown to be inhibited by the addition of PMe3. 



54 

The reactivity of the bis-neopentyl derivative, 25, involving molecular hydrogen will be the 
focus of Chapter 4, and will draw on many of the same principles discussed in this chapter. 



CHAPTER 4 
FORMATION OF W(VI) HYDRIDES FROM THE BIS-ALKYL COMPLEXES 



4.1. High Oxidation State Transition Metal Hydride Complexes 

The synthesis of high oxidation state transition metal hydride and polyhydride 
complexes is a highly active area of chemical research. 61 - 62 Complexes containing M-H 
bonds have long been known to be important intermediates in a plethora of catalytic 
processes. 62 ' 63 The hydrogenation of olefins, both catalytic and stoichiometric, is one of 
the most important functions of transition metal hydride complexes. 61 ' 64 Recently, 
Rothwell even demonstrated the catalytic hydrogenation of benzene using a tantalum(V) 
hydride complex. There are a number of methods that have been utilized in the preparation 
of these hydride complexes. One common preparative method is the high pressure 
hydrogenation of metal-alkyl bonds. 61 ' 62 Another means of preparing hydride complexes 
is the oxidative addition of hydrogen to lower oxidation state compounds such as W(rV) 
and Ta(ni). 61 ' 62 ' 66 Transition metal hydride complexes have also been prepared by 
utilizing hydride reagents such as n-Bu3SnH or LiBEt3H 67 Because of its small size, 
many hydrides have coordination numbers greater than six. Also, most monomelic 
hydrides are stabilized by strong o-donors ligands, such as phosphines. 

4.2. Preparation of W(VD Hydride Complexes. 

There have been many reports of the hydrogenation of high oxidation state alkyl 
complexes to give hydrides, however, frequently these reactions are performed under 
forcing conditions (extremely high pressures of hydrogen in the presence of phosphine 
ligands at elevated temperatures). 61 - 62 Rothwell observed the reaction of hydrogen and 



55 



56 



Ta(R)2(OAr)3 to give Ta(H)2(OAr)3(PR.3) in the presence of phosphine. 68 This reaction 
was carried out at 90 °C under 8300 kPa of hydrogen for 24 hours eq 4.1. These 
OAr OAr 

-OAr + PMe 2 Ph ^ H 2 (1200 psi) , p^p^Ta _ Ar eq4.1 

90°C,24hrs -jT \ 

R 



R-.. 



OAr 



R = CH 2 C6H4-p-Me; 
OAr - OC 6 H3-2,6-Pi i 2 



OAr 



conditions are typical for the hydrogenation of alkyl compounds and are quite harsh. 
Similar conditions were not necessary for the hydrogenation of some of the bis-alkyl 
complexes discussed in Chapter 3. When W(NPh)(CH2CMe3)2[(Me3SiN)2C6H4], 25, 
was placed under two atmospheres of hydrogen in the presence of two equivalents of PMe3 
at room temperature, the conversion of the bis-neopentyl to a new dihydride complex was 
complete in less than two hours. The dark brown solution turned magenta, and small red 
crystals precipitated from solution eq 4.2. The new complex was the seven coordinate 
dihydride, W(NPh)(H)2(PMe3)2[(Me3SiN) 2 C6H4], 39. 



Me 3 Si //} 

\ Me 3 P 1=/ 




+ 2 PMe3 



H 2 



hexanes 
room temp 




/> 



N 



W- 



'/ 



AX 

Me3P 



H eq4.2 



Me 3 Si 



39 



Compound 39 was characterized by multinuclear NMR and X-Ray 
crystallography. At room temperature, the *H NMR spectrum reveals the hydride 
resonances as a broad triplet at 9.28 ppm with a peak separation of 38 Hz. The two PMe3 
groups appeared as a singlet at 1.04 ppm, while the silyl methyls were inequivalent singlets 
at 0.79 and 0.81 ppm, respectively. The two phosphines were observed as a singlet at 



57 

-24.46 ppm ( ! Jw-H = 188 Hz) in the 31 P NMR spectrum. When the *H NMR spectrum 
was taken at -50 °C, numerous changes were observed. First of all, the PMe3 resonance 
resolved into a triplet with a peak separation of 3 Hz at 0.84 ppm. Secondly, the silyl 
methyls separated further, resonating at 0.69 and 0.75 ppm. The hydrides appeared as a 
doublet of doublets at 8.92 ppm and 9.06 ppm respectively. The apparent coupling was 37 
Hz. 

Unfortunately, high quality single crystals of 39 have not yet been obtained. 
Numerous attempts were made to acquire crystallographic data on 39. Some data was 
collected although an accurate structure could not be determined. The data suggest the 
presence of frarcs-phosphines with the amido and imido nitrogens in the equatorial plane. 
In order to have equivalent phosphines and inequivalent hydrides, the hydrides probably lie 
cis to each other, in the plane of the imido and amido nitrogens. This geometry, shown in 
eq 4.2, should give an ABX2 resonance for the hydrides, which would be a doublet of 
triplets. The doublet of doublets observed at low temperature are very broad and may be 
due to a second order effect. A concerted effort is currently underway to obtain an X-ray 
structure of 39. The PMe2Ph derivative, W(NPh)(H)2(PMe2Ph) 2 [(Me 3 SiN) 2 C6H4], 40, 
was prepared in an analogous reaction. The hydride ligands were observed as a broad 
singlet at 9.80 ppm in the l H NMR spectrum at room temperature. At -50 °C, a triplet at 
9.56 ppm was observed with 39 Hz coupling, analogous to 39. The 31 P NMR spectrum 
revealed a singlet at -22.48 ppm with 183 Hz 183 W satellites. The PMe2Ph derivative was 
prepared in the hopes growing better crystals, since most of the structurally characterized 
hydrides are the PMe2Ph derivative. 61 - 62 ' 67 

The seven-coordinate dihydride, 39, should serve as an excellent model to study 
the reactivity of dihydride complexes. Therefore, a more convenient route to the synthesis 
of this compound would be useful. Avoiding the alkylation step and adding hydride to the 
dichloride, 14 would be a viable route. Two equivalents of superhydride, LiBEt3H, were 
allowed to react with 14 in cold Et20. Work-up afforded 39 as a brown-red powder. 



58 

There was residual BEt3 which could not be removed from the compound. Although this 
reaction was important in showing the ability of 14 to add hydride, it was not employed to 
make the hydrides for the reactivity studies. 

When two equivalents of PCy3 were utilized as the phosphine ligands, the steric 
bulk of the ligand prevented isolation of the analogous bis-phosphine complex. Although 
combustion analysis has not been performed because of the excess phosphine present, the 
spectral data are consistent with the isolation of the monophosphine complex 
W(NPh)(H)2(PCy3)[(Me 3 SiN)2C6H 4 ], 41, eq 4.3. The X H NMR spectrum of 41 
reveals a doublet at 1 1.35 ppm ( 2 Jp-H = 83 Hz). 



Me3Si 
Me 3 Si T \ 

Vt N / 

W + pCy 3 




xK^ f "N . / hexanes 

N \ room temp 

Me 3 Si 25 




Me 3 Si 



Satellites due to the !83\y lj w . H coupling were observed at 64 Hz. The silyl methyl 
groups were observed as a singlet at 0.83 ppm. The 31 P NMR spectrum of 41 reveals a 
singlet at 66.53 ppm (^p-H = 83 Hz). 

The chelating nature of the bis-amide ligand again dictates the geometry of the 
molecule. Rothwell prepared Ta(OAr)2Cl(H)2(L)2 derivatives using PMe3, PMe2Ph, 
PMePh2. 68 The structures of these compounds reveal that the phosphines are always trans 
to one another. In these compounds, the aryloxides are always trans to one another as 
well. This differed from 39 and 40 in which the amide nitrogens must be cis to one 
another because of the chelating nature of the ligand. In order to investigate the role of the 
trans phosphines, and to fine out whether or not cis phosphine complexes were stable, a 
chelating phosphine was selected. Diphenylphosphinoethane, DPPE, was utilized in a 



59 

reaction similar to eq 4.2. The new hydride was found to be 
W(NPh)(H)2(DPPE)[(Me3SiN)2C 6 H 4 ], 42, eq 4.4. 

The *H NMR spectrum of 42 reveals a very symmetrical molecule. The silyl 
methyls were observed as a singlet at 0.49 ppm. The methylene protons of the DPPE 
ligand were observed as multiplets at 2.23 and 2.42 ppm. The hydrides were equivalent at 
all temperatures observed. At room temperature the hydrides appeared as a complex 
multiplet which can be viewed as the X part of an ABX2 spin system where the phosphines 
are A and B. Satellites due to 183\y coupling were observed at 58 Hz for each of the peaks 
in the spectrum. The *H NMR spectrum of the hydride region can be seen in Figure 4.1 . 





Me 3 Si 

v N vii/~^ „ 2 rrvM^ * 

W +DPPE «- i W- P eq4.4 

Ay \-f ***** [ IA / 1 V Ph 

N \ room temp \^ x j/ ?—-/ 

Me 3 Si 25 / Ph Ph 

Me3Si 

42 

The phosphines were inequivalent in the 31 P NMR spectrum, and appear as doublets, at 
-12.70 and 30.43 ppm, respectively ( 2 Jp.p = 83 Hz). The geometry of this seven- 
coordinate dihydride can be inferred from the NMR data. Having one leg of the DPPE 
bisect the two hydrides is the only possible geometry giving both equivalent silyl methyls 
and hydrides as well as inequivalent phosphines. 

There are few examples of high oxidation state hydride complexes where strong o~- 
donor ligands are not coordinated to the metal center. Coincident with this is that there are 
few coordinatively unsaturated high oxidation state hydride complexes. One of the few 
examples resulted when Rothwell hydrogenated Ta(OAr)3(CH2C6H4-4-Me)2 under 1200 
psi of hydrogen at 90 °C for 24 hrs to give Ta(H)(OAr)4 in low yield. 68 The monohydride 



60 




R "* 



U 

'* g 
CO 

o 



W 

CM 

'. § 






O 

rt 

o 

"Eb 
S 
o 



O 

•s 

O 



a 



o 

P« 

P4 






as 
u 



61 

is presumably formed in a ligand exchange reaction. There are also metallocene derivatives 
of the type CP2MH2, but these will not prove insightful to this discussion. 69 

When phosphine was present upon hydrogenating the bis-neopentyl complex, 25, 
the reaction was complete in a matter of hours. When no phosphine was added to the 
reaction, the hydrogenation proceded much more slowly, and allows an examination of the 
mechanism of the reaction. When H2 gas was sealed in an NMR tube containing a C^Ds 
solution of 25, hydrogenation of the metal carbon bonds took place in a matter of days. 
The rate was dependent on the pressure of H2 gas. When a very low pressure of gas, < 20 
psi was sealed in the tube, the reaction took nearly a week to reach completion. However, 
when 30 psi of H2 was used, the reaction was complete in about 36 hours. The product is 
only observable under an atmosphere of H2 gas. The product of the hydrogenation was 
presumably a dimer due to interpretation of the NMR data. The silyl methyl groups were 
observed as a singlet at 0.33 ppm in the *H NMR spectrum. Two equivalents of 
neopentane were observed at 0.93 ppm. The spectrum also reveals a singlet at 15.68 ppm 
with 168 Hz 183 W satellites corresponding to the two hydrides. The tungsten satellites 
were actually observed as doublets, J = 4 Hz. The observation of the tungsten satellites as 
doublets was the key evidence in proposing a dimeric structure. Cotton observed a similar 
coupling effect in the W2Cl4(NHCMe3)(PR3)2 system. 69 The only observable satellites 
will be from a dimer with only one 183 W, due to only 14% abundance. This would 
constitute an ABX spin system, resulting in a doublet of doublets. The hydride resonance 
is shown in Figure 4.2. The shift of the hydrides was in the normal range for high 
oxidation state group 5 and 6 complexes in the literature. 61 " 68 Evidence for proposing 
bridging imido groups will be given later in the chapter. The reaction is shown in eq 4.5. 
When the sample was evaporated to dryness, the dihydride isomerized or rearranged, 
forming what appeared to be a bridging hydride. When the sample was redissolved in 
C6D6, the *H NMR spectrum changed dramatically. At room temperature, the hydrides did 
not appear in the spectrum, although a broad increase in the integral was observed between 



Me 3 Si x 

N ^ N 

1 25 
Me 3 Si 25 



■f 



H 2 , 20 psi 

» 

hexanes 

room temp 

36 hours 



62 



Me 3 Si 



SiMe 3 



\ / 

N* H N H ,N 

Me 3 Si [l] SiMe 3 



43 



11 and 13 ppm. When the sample was cooled to -25 °C, a sharp singlet at 12.58 ppm and a 
broad singlet at 15.80 ppm were observed in a 1:1 ratio. When the sample was cooled 
further, to -50 °C, the sharp singlet remained unchanged while the broad singlet split into 
two broad singlets at 15.28 ppm and 1 5.98 ppm respectively. The ratio of the three peaks 
was observed to be 2:1:1. The broad singlets are consistent with being bridging hydrides, 
while the sharp singlet appears to be the terminal hydrides. The sharp singlet actually had 
satellites at 53 Hz and 100 Hz. Although the true identity of the molecule cannot be 
confirmed, it is assuredly still a dihydride complex of sorts. When two equivalents of 
PMe3 were added to the sample, the bis-phosphine dihydride, 39, was formed by 
observation of the l H NMR. There is not enough known at this time to make more 
substantial conclusions, but work is continuing in this area. 

As was mentioned earlier, since the hydrogenation, at very low pressures of H2, 
takes a number of days, an opportunity to observe intermediates and deduce a mechanism 
was presented. In an NMR tube reaction, 25 was dissolved in C6D6 and sealed under an 
atmosphere of less than 20 psi H2. After twelve hours, the l U NMR revealed four 
compounds in the reaction mixture. There was 25% starting material, neopentane, and two 
new compounds, the metallacyclobutane, 35, and a monohydride complex, 44 eq 4.6. 
The spectrum reveals the two doublets, at -1.7 and 2.1 ppm, which correspond to the 
metallacyclobutane complex discussed in Chapter Three. 



63 



64 



Me 3 Si 



a: 



vll 

w 



Me 3 Si 



./ 



25 



■f 



H 2 , <20psi 



room temp 
1 2 hours 



Me,Si 



"^Y 




Nfc 



N 



<6* 



Me,Si 



vll. 
w 



44 



•c6 J 

Me 3 Si 35 




eq4.6 



The monohydride, W(NPh)(CH2CMe3)(H)[(Me3SiN)2C6H4], 44, was characterized by a 
singlet at 18.43 ppm (^w-H =151 Hz). The methylene protons of the monohydride- 
neopentyl complex appeared diastereotopic with a doublet at 2.60 ppm and a broad singlet 
at 3.28 ppm. As the reaction was observed over the course of the following 3 days, the 
bis-neopentyl complex, 25, disappeared completely and the dihydride complex, 43, grew 
in. Over the course of a number of trials of this NMR tube reaction, it was observed that 
the bis-neopentyl reached at least 90% completion before dihydride formation initiated. 

The metallacyclobutane complex was thought to be in an equilibrium with the 
monohydride complex under an H2 atmosphere. The metallacycle was formed when H2 
was lost from the monohydride by a net y-hydrogen elimination mechanism. The reverse 
reaction takes place when H2 was added across one of the W-C bonds of the metallacycle 
eq 4.7. This equilibrium was 




-H 2 



+H 2 




eq4.7 



Me 3 Si 35 

demonstrated by adding H2 to an NMR tube containing a CgDg solution of 25, then 
degassing the reaction after eight hours. The l H NMR spectrum, which was taken 
immediately after degassing, revealed the three compounds expected, 25, 35, and 44 in 
roughly a 1:1:3 ratio. Over the course of two weeks, the reaction was degassed 



65 

periodically. During this time, the bis-neopentyl complex was completely consumed. 
Also, as the reaction proceeded, the monohydride decreased and was only observable in 
trace amounts. Figure 4.3 demonstrates how only a catalytic amount of hydrogen was 
necessary for complete conversion of the bis-neopentyl complex to the metallacycle. 




Figure 4.3. Formation of the metallacycle, 35, by the addition of a 
catalytic amount of H2 to the bis-neopentyl complex, 25. 



All of the observations which have been made pertaining to the hydrogenation of 
25 in the absence of PMe3 were from NMR tube experiments. When complete 
hydrogenation of 25 was carried out on a preparatory scale only the bridging hydride was 
isolated. It appears to be the same bridging hydride which was observed when 43 was 
evaporated to dryness and redissolved in C6D6. When a pentane solution of 25 was stirred 
under two atmospheres of H2 for 36 hours and cooled to -10 °C, dark crystals were formed 
which were suitable for X-ray diffraction. 

The X-ray structure revealed a unique dimeric structure. The thermal ellipsiod plot 
of 45 is shown in Figure 4.4. The structure was interesting since there is a neopentyl 



66 




<-l-c 

o 
o 

-a 

-t-H 

o 

CO 

.& 

»-— t 

W 

13 






3 



67 

group on one of the tungsten atoms and not on the other. Both of the imido groups were 
bridging and both the nitrogen's lie slightly closer to the tungsten without the neopentyl 
group, probably in order to relieve steric congestion. The bridging hydride was located 
and refined. It was found to be 2.07(10)A from Wl and 1.87(1 1)A from W2. Although 
the terminal hydrides were not found in the difference Fourier map, there appears to be 
open coordination sites which could accommodate the terminal hydrides, both on the 
unsubstituted tungsten. The open coordination sites are in the axial positions. The fold 
angle of the bis-amide ligand on the neopentyl substituted tungsten was 54 °. The fold 
angle of the bis-amide ligand on the unsubstituted tungsten was °. The planarity of the 
bis-amide ligand would be due to the seven-coordinate nature of the tungsten atom. The 
l B. NMR of 45 reveals that the molecule is quite fluxional, with all of the hydrides 
appearing as a very broad singlet at 12.9 ppm. 

Hydrogenation of the bis-neophyl complex, 26, gave results similar to 25. 
However, the metallacycle was always observed in a much lower ratio than in the bis- 
neopentyl hydrogenation. This was probably because the p-methyl, {3'-phenyl- 
metallacyclobutane complex was much less stable than the p,pY-dimethyl- 
metallacyclobutane complex. Therefore, it loses H2 and reverts to the monohydride much 
more readily. 

Another means of investigating this equilibrium was to examine the effect of added 
phosphine to the reaction mixture. Once the equilibrium was established and the reaction 
degassed, one equivalent of PMe3 was added to the reaction mixture. Surprisingly, the 
alkylidene, 36, was formed almost immediately. This reaction proceeds by an cc-hydrogen 
abstraction from the monohydride complex, eliminating H2, or possibly rearrangement of 
the metallacycle. The H2 released then adds to the metallacyclobutane, forming more 
monohydride to react with the phosphine. The mechanism for this reaction can be seen in 
Figure 4.5. This would be the first example of an a-abstraction involving the loss of 
hydrogen to form an alkylidene. Undoubtedly, reductive elimination of neopentane would 



68 



be a more expected than a-abstraction. The implications of such a mechanism contradict 
many of the criterion which dictate a-abstraction reactions in high-oxidation state transition 




Me 3 Si' 36 

Figure 4.5. Mechanism for the formation of the alkylidene by 
a-abstraction from the equilibrium mixture of 35 and 44. 



metals. Certainly no steric relief was gained by the elimination of H2. The W-C a -Cp angle 
decreases from an alkyl to an alkylidene but that is overshadowed by the addition of PMe3 
to the metal center. 

This brings up the question of the hydrogenation of the alkylidene. When a C&D6 
sample of 36 and one equivalent of PMe3 was placed under two atmospheres of H2, the 
dihydride, bis-phosphine complex, 39, was formed in a matter of hours eq 4.8. A 
different observation was made when the alkylidene was hydrogenated under an extremely 
low pressure of H2 in the absence of 'added' phosphine. Over the course of ten days, the 
alkylidene was completely consumed to give a one to one mixture of two products and one 
equivalent of neopentane. The two products were the dihydride, bis-phosphine complex, 
39, and the metallacyclobutane complex, 35. The two products were most likely formed 



69 

by the disproportionation of the intermediates since there were less than two equivalents of 
H2 added. 



,\^r) u "\^P 



Me 3 Si tik 

Vt It 

- N vll. 



^ 




N 



A /\ + pmc 3 H? ' 2atm > I /T>T H eq4 " 8 



N PMe 3 




Me 3 Si / 36 I Me 3 P 

Me 3 Si 39 



N 



It cannot be denied that there appears to be a number of loose ends in the chemistry 
of these new hydride complexes, especially in the absence of phosphines. However, it is 
also undeniable that there was a wealth of information that lead to the conclusions which 
were made. Although isolation of a number of these compounds is unlikely due to their 
instability, crystallographic data on one or more of these compounds would be quite 
insightful. The discovery of an example a-hydrogen abstraction involving the 
monohydride-neopentyl has enormous implications and will be investigated further. 

4.3. Reactivity of the Dihydrides. 

High oxidation state transition metal hydrides complexes are known to hydrogenate 
olefins both stoichiometrically and catalytically. 62 - 63 Rothwell even demonstrated the 
hydrogenation of arenes using Ta(V) dihydrides.65 Coordination of the olefin was an 
essential step in the reaction. Olefins are ^-acceptor ligands and require filled metal d- 
orbitals to facilitate back-bonding. Therefore cP olefin complexes are unlikely. 
Nonetheless dS and <fi complexes should have sufficient orbitals to overlap with an olefin 
acceptor orbital, stabilizing a 7t-olefin complex. Ligands with a strong electronic donation 
to the metal center should aid in the isolation of coordinated 7t-olefin complexes. Imido 
ligands (=NR) 2_ are strong 7t-donors because of the lone electron pair and should aid in the 



70 



isolation of 7t-olefin complexes. Strong a-donors, such as phosphines should also aid in 
creating a suitable electronic environment for 7t-olefin complexes. Currently, there are very 
few examples of d 1 or d 2 Tt-olefin complexes which have been thoroughly characterized. 71 
Therefore, the isolation of jt-olefin complexes is essential to the advancement of this 
chemistry. 

Initial investigation into the reactivity of some of the phosphine stabilized hydride 
complexes, 39 and 42, has begun. When a C6D6 sample of 

W(NPh)(H)2(PMe3)2[(Me3SiN)2C6H4], 39, in a sealable NMR tube was placed under an 
atmosphere of ethylene, ethane formation was observed by the observation of a singlet at 
1.1 ppm in the *H NMR spectrum. A second equivalent of ethylene was bound to the 
reduced metal center, forming the W(IV) ethylene complex, W(NPh)(ri 2 - 
C2H4)(PMe3)2[(Me3SiN)2C 6 H 4 ], 46, eq 4.9. The *H NMR spectrum of the ethylene 
complex reveals that the compound is quite fluxional at room temperature. 



Me 3 Si 

\ Me 3 P 

w; 





Me 3 Si PMe 3 {? ]| 

N. 




2C 2 H 4 



Me 3 P 



Me 3 Si 



/ 




+ C 2 H 6 eq 4.9 



39 



N 

/ Me 3 P 
Me 3 Si 46 



The room temperature X H NMR spectrum is shown in Figure 4.6. The ethylene protons 
were observed as two multiplets at 1.96 and 2.19 ppm respectively. The coupled 13 C 
NMR spectrum revealed a triplet at 36 ppm corresponding to the ethylene carbons. The 
iJc-H coupling of the carbons was 156 Hz, typical for an ethylene complex, indicating that 
little 'metallacyclopropane' character was evident 71 . The PMe3 ligands were equivalent 
and were observed at 1.05 ppm in the ] H NMR spectrum. At room temperature, the 31 P 
NMR spectrum revealed a broad singlet at -23.2 ppm while at -25 °C, a sharp singlet at 
-21.77 ppm with 238 Hz 183 W satellites was observed. The silyl methyls appeared as a 



71 





U 
o 

CO 

cN 
*-> 

cd 

SO 



& 

CO 

CO 



CS 

"en 

o 
.p- 



t*-i 



o 
o 

Pi 





»— 1 



^° 
u 

3 

•Ml 



72 

broad singlet, nearly 120 Hz wide, at 0.50 ppm in the l H NMR spectrum at room 
temperature. When the sample was cooled to -25 °C, two sharp singlets were observed at 
0.39 ppm and 0.42 ppm. A tantalum ethylene complex prepared by Schrock 72 and 
tungsten olefin complexes prepared by Nielson 73 show that the ethylene prefers to 
coordinate cis to the imido. The ethylene also preferred to coordinate cis to phosphine 
ligands. In every case, the ethylene coordinated trans to an 'X' ligand. Nielson obtained 
crystallographic data on W(NPh)Cl2(Me2C=CH2)(PMe3)2 which clearly demonstrated this 
geometry. 73 The spectral data for 46 were consistent with these compounds and support a 
trans phosphine structure. Difference nOe experiments on 46 showed that upon irradiation 
of the orf/?o-protons of the imido group, a 4.8% enhancement was observed for the 
coordinated ethylene. This substantiates the cis orientation of the imido and the ethylene. 

A W(IV) olefin complex was also formed when two equivalents of styrene was 
allowed to react with the dihydride, 39. In an NMR tube experiment, formation of 
ethylbenzene was observed along with formation of the styrene complex, W(NPh)(r| 2 - 
CH2CHPh)(PMe3)2[(Me3SiN)2C6H4], 47. The olefinic peaks were observed as sharp 
multiplets at 2.62 and 2.80 ppm and a triplet at 3.87 ppm in a 1:1:1 ratio. The orientation 
of the coordinated styrene is not known, although it appears by NMR that only one 
orientation is adapted. 

When the catalytic hydrogenation of ethylene and cyclooctene was attempted using 
the dihydride, 39, mixed results were observed. Cyclooctene and H2 were added to an 
NMR sample of 39. Over time, even with mild heating, it did not appear as though any 
cyclooctene was hydrogenated by observation of the NMR. It was already known that one 
equivalent of ethylene is stoichiometrically hydrogenated by 39, so detection of catalysis 
by NMR proved difficult. It appeared as though, over days, that the ratio between the 
ethylene and the ethane appeared to decrease. Further work will be focused on this 
reaction. 



73 

The reaction of ethylene and the DPPE dihydride, 41, did not yield an ethylene 
complex. Instead, no reaction was observed at room temperature over three days. 
However, when a purple C^ solution of 41 and ethylene was heated to 90 °C for 12 
hours, the color changed to yellow. The ! H NMR revealed that DPPE had been lost from 
the metal center. The resonances corresponding to the hydrides and free ethylene were also 
no longer present. The product formed appears to be a metallacyclopentane complex 
formed by the addition of two equivalents of ethylene to the metal center. 74 The overall 
reaction can be seen in eq 4.10. The complex appeared to have 



rr^ 




Me 3 S 



xs C 2 H 4 



80 °C 



42 




+ DPPE eq4.10 



a plane of symmetry due to the observation of a singlet at 0.31 ppm in the l H NMR 
spectrum and two AA'BB' multiplets at 7.1 1 ppm and 7.41 ppm. The metallacyclopentane 
protons were observed as three multiplets, at 1.58 ppm, 2.41 ppm, and 2.89 ppm in a 
2:2:4 ratio. 

A reaction that is important to mention at this point is the reaction of excess ethylene 
with the bis-neopentyl complex, 25. When ethylene was allowed to react with a C^ 
solution of 25, the ! H NMR revealed that 1-butene was released. The formation of 1- 
butene was very slow but very clean, a 60:40 mixture of ethylene and 1-butene was 
observed after 14 days at room temperature. Throughout the reaction, the concentration of 
25 remained virtually unchanged while formation of other organometallic products was not 
observed. After 14 days, the sample was heated to 80 °C for 8 hours. The ! H NMR 
spectrum revealed that all of the ethylene had been consumed. There was no bis-neopentyl 
complex observable in the NMR, although the large amount of 1-butene obscured much of 



74 



the spectrum. The sample was degassed thoroughly. The *H NMR revealed that the 
organometallic product was identical to the proposed metallacyclopentane complex from the 
reaction of 42 and ethylene. 

The fact that 1-butene formation was observed without observation of a new 
organometallic compound suggests that a very small amount of an active catalyst was being 
produced at room temperature. At higher temperature, all of the bis-neopentyl must be 
converted to the active catalyst. The formation of 1-butene from the metallacyclopentane 
complex would go by a simple (3-hydrogen elimination reaction. Therefore, the formation 
of the metallacyclopentane is the key step of the reaction. The formation of 
metallacyclopentane compounds from addition of two equivalents of ethylene to a low 
oxidation state metal center is well known. 2 ' 74 > 75 These metallacyclopentane complexes 
are also known to undergo (3-hydrogen elimination reactions, forming 1-butene. The 
formation of a reduced metal species, W(IV), in this case, would be formed by the 
reductive coupling of the two neopentyl groups. The mechanism for this reaction can be 
seen in Figure 4.7. 

Most of the work reported in this chapter involves very recent results, and has 
brought up many new questions as well as areas for future work. Other members of the 
research group will continue this work, and hopefully continue to make great strides in this 
area. 



Me,Si 



a; 



N. N 

W' 



X 



xs C->H. 



-(M&jCCHjJj 



Mc 3 Si 



i-hydrogcn dim. 




[W] 



> 

^ 



Mc,Si 



N*. N 



' /"--■~. 



coo 



McjSi 



Figure 4.7. The catalytic formation of 1-butene from the addition of 
ethylene to the bis-neopentyl complex, 25. 



CHAPTER 5 
EXPERIMENTAL 



Unless otherwise noted, all procedures were performed under dry argon 
atmosphere using standard Schlenk techniques or in a nitrogen atmosphere dry box. All 
solvents were dried according to established literature procedures. 

*H, 13 C and 31p NMR spectra were recorded on a Varian VXR-300 (300 MHz), a 
General Electric QE-300 (300 MHz), or a Varian Gemini-300 (300 MHz) spectrometer. 
Chemical shifts were referenced to the residual protons of the dueterated solvents and are 
reported in ppm downfield of TMS for *H and 13 C NMR spectra. 31 P NMR were 
referenced to an external H3PO4 standard. Elemental analysis were performed by Atlantic 
Microlabs, Inc., Norcross, GA. 

Preparation of N.N'-bis(trimethylsilyl)-o-phenylenediamine. 1: 

Trimethylsilylchloride (12.7 mL, 0.10 mol) was added slowly to a solution of o- 
phenylenediamine (5.00 g, 0.047 mol) in 50 mL of Et20. A white precipitate formed upon 
addition. Triethylamine (13.9 mL, 0.10 mol) was then added slowly, ensuring that stirring 
continued throughout the addition. After stirring for 3 hours at room temperature, the 
mixture was filtered and the solid was washed twice with 15 mL of Et20. The filtrate was 
stripped of solvent under reduced pressure to give 10.2 grams of a yellow solid; yield, 
86.8%. M.P.;29.5°C. 



75 



76 
Preparation of Liori^-rNSiMeV bC^FL;!. 2: 

A solution of N,N'-bis(trimethylsilyl)-o-phenylenediamine (5.26 g, 20.9 mmol) in 
75 mL of pentane was cooled to -78 °C. To this solution, 2 equivalents of n-BuLi (16.8 
mL, 41.9 mmol, 2.5 M sol. in hexanes) was added slowly. A white precipitate formed as 
gas was evolved. Upon addition, a bubbler was attached and the reaction was stirred at 
room temperature for 2 hours under a flow of argon. The mixture was filtered and the 
solid dried under reduced pressure. The volume of the filtrate was reduced to 25 mL under 
reduced pressure and cooled to -15 °C to give colorless crystals. Yield; 4.93 g (combined), 
89.5%. 

Preparation of N.N'-bisfdimethylphenylsilylVo-phenylenediamine. 3: 

O-phenylenediamine (1.58g, 14.64 mmol) was slurried in 50 mL of hexanes. Two 
equivalents of both dimethylphenylsilylchloride (4.90 mL, 29.29 mmol) and triethylamine 
(4.08 mL, 29.29 mmol) were added via syringe. The mixture was then refluxed for 12 
hours. Upon cooling, a white salt precipitated from solution. The mixture was filtered. 
The yellow solution was stripped of solvent under reduced pressure to give 4.86 grams of 
a yellow/red solid; yield, 87.0%. Anal. Calc'd for C22H28N2S12: C, 70.15; H, 7.49; N, 
7.44. Found: C, 69.89; H, 7.28; N, 7.21. 

Preparation of N.N'-bis(methyldiphenylsilyl)-o-phenylenediamine. 4: 

O-phenylenediamine (0.64 g, 5.94 mmol), methyldiphenylsilylchloride (2.50 mL, 
11.81 mmol) and triethylamine (1.82 mL, 13.00 mmol) were reacted as described above 
for 3 to give 2.09 grams of a reddish solid; yield 70.3%. Anal. Calc'd for C32H32N2Si2: 
C, 76.75; H, 6.44; N, 5.60. Found: C, 76.39; H, 6.23; N, 5.27. 



77 

Preparation of N.N'-bis(trimethylsilyl)-4.5-dimethyl- 1 .2-diaminobenzene, 6: 

4,5-dimethyl-l,2-diaminobenzene (5.11 g, 37.52 mmol), trimethylsilylchloride 
(9.52 g, 75.05 mmol), and triethylamine (10.53 mL, 75.05 mmol) were reacted as 
described above for 3 to give 9. 12 grams of a yellow solid; yield, 88.53%. Anal. Calc'd 
for Ci 4 H28N 2 Si 2 : C, 59.93; H, 10.06; N, 9.99. Found: C, 60.13; H, 10.29; N, 10.21. 

Preparation of N.N'-(trimethylsilyl)-1.8-diaminonapthalene. 7: 

1,8-diaminonapthalene (10.61 g, 67.07 mmol), trimethylsilylchloride (17.87 mL, 
140.84 mmol), and triethylamine (19.63 mL, 140.84 mmol) were reacted as described for 
3 above to give 18.15 grams of a red solid; yield, 89.4%. Anal. Calc'd for C16H26N2S12: 
C, 63.49; H, 8.67; N, 9.27. Found: C, 63.17; H, 8.39; N, 9.08. 

Preparation of N-phenyl. N'-trimethylsilyl-o-phenylenediamine. 8: 

N-phenyl-o-phenylenediamine (1.53 g, 8.28 mmol), trimethylsilylchloride (1.18 
mL, 8.50 mmol), and triethylamine (1.08 mL, 8.50 mol) were reacted as described above 
for 3 to give 1.64 grams of a reddish solid; yield; 77.2%. Anal. Calc'd for Ci5H2oN2Si: 
C, 70.24; H, 7.87; N, 10.93. Found: C, 69.91; H, 7.68; N, 10.73. 

Preparation of l^-q PrNHbC^FU 9 and l^NfmCfMebCHoCHfMeWfH^-C^ 10 

O-phenylenediamine (2.5 g, 23.12 mmol) and sodium acetate (7.21 g, 87.9 mmol) 
were slurried in 15 mL of acetic acid, 20 mL of acetone, and 40 mL of H2O. The mixture 
was stirred for 30 minutes in an ice bath. NaBIL; (14.97 g, 277.4 mmol) was added 
slowly. Upon addition, the reaction was allowed to warm to room temperature and was 
stirred for one hour. NaOH (6 M solution) was added until slightly basic by litmus test. 
The mixture was then extracted with Et20 (2 x 20 mL). The Et20 was removed in vacuo to 



78 

yield a red oil. The oil was separated by flash chromatography on a Silica column using 
hexanes. The heterocyclic compound l,2-[N(H)C(Me)2CH 2 CH(Me)N(H)]-C6H 4 10, 
was eluted first, solvent was striped in vacuo to give a white powder (1.31 g, 41.1%). 
Anal. Calc'd for Ci 2 H 2 oN 2 : C, 75.80; H, 9.47; N, 14.74. Found: C, 75.71; H, 9.64; 
N, 14.75. The diamine, l,2-( i PrNH) 2 C6H4 9, was eluted last and was isolated by cooling 
the hexanes solution to -78 °C to yield a white powder, which melted to a colorless oil upon 
warming (0.87 g, 29.3 %). 

Preparation of 1.8-rN(H)C(MebNnHmQ mH4 11 



1,8-Diaminonapthalene (2.57 g, 16.25 mmol) and sodium acetate (5.06 g, 61.75 
mmol) were slurried in 10 mL of acetic acid, 20 mL of acetone, and 40 mL of H 2 0. After 
stirring in an ice bath for 30 minutes, NaBH4 (15.95 g, 285.9 mmol) was added slowly. 
Upon addition, the reaction was allowed to warm to room temperature and was stirred for 
one hour. NaOH (6 M solution) was added until slightly basic by litmus test The mixture 
was then extracted with Et 2 (2 x 20 mL). The Et 2 was removed in vacuo to yield red 
powder (2.96 g, 91.9%). Anal. Calc'd for Ci 3 Hi 4 N 2 : C, 78.76; H, 7.12; N, 14.13. 
Found: C, 78.22; H, 7.09; N, 14.49. 

Preparation of WQCb^NSiMeV bC^FL I. 13: 

WOCL4 (1.00 g, 2.93 mmol) and 1.1 equivalents of Li 2 [l,2-(NSiMe3) 2 C6H4] 2 
(0.85 g, 3.20 mmol) were combined in a Schlenk tube and cooled to -78 °C. 50 mL of 
Et 2 which had been cooled to -78 °C was added. The reaction was warmed to room 
temperature and stirred for 8 hours. Solvent was removed under reduced pressure. The 
solid was extracted with 50 mL of pentane and filtered through a Celite pad. The dark 
solution was cooled to -78 °C to afford a dark red powder (0.39 g, 25.6% yield). Anal. 
Calc'd for Ci 2 H 2 2N 2 OCl 2 Si 2 W: C, 27.65; H, 4.26; N, 5.37. Found: C, 27.61; H, 4.29; 
N, 5.41. 



79 

Preparation of WfNP^CbrfNSiMe^ bC^rL I. 14: 

N,N'-bis(trimethylsilyl)-o-phenylenediamine 1 (3.83 g, 15.16 mmol) was 
dissolved in 30 mL of Et20 and cooled to -78 °C. Two equivalents of n-BuLi (12.13 mL, 
30.32 mmol, 2.5 M soln in hexanes) were then added. The reaction was warmed to room 
temperature and stirred for one hour. The reaction was recooled and .95 equivalents of 
W(NPh)CU(OEt 2 ) (7.10 g, 14.4 mmol) in 20 mL of Et 2 was added. The reaction was 
stirred for three hours, then filtered through a celite pad, which, in turn, was rinsed with 
more Et20. Solvent was removed under reduced pressure. The dark red solid was washed 
with pentane until an orange powder remained. The powder was dried to yield 7.31 g of 
14; 85.1%. Anal. Calc'd for Ci 8 H27N 3 Cl2Si2W: C, 36.25; H, 4.56; N, 7.05. Found: 
C, 35.91; H, 4.78; N, 6.78. 

Preparation of l.S-KoCMe^SiNlC iinm 16 and L8-Li 2 (Me3_SiN)O inH£. 17 

1,8-Diaminonapthalene was dissolved in pentane and cooled to °C. Two 
equivalents of either KH or n-BuLi were then added. The reactions were allowed to warm 
and stirred for one hour. Yellow precipitate formed during the reaction. Cooling the 
reaction mixtures to -10 °C afforded nearly quantitative yields of the corresponding salts as 
yellow crystals. 

Preparation of WfNPh^Cbri^-CNSiMe^ bOinH *!. 18: 

l,8-(NHSiMe 3 ) 2 CioH6 7 (1.28 g, 4.23 mmol) was dissolved in 25 mL of Et20 
and cooled to 78 °C. Two equivalents n-BuLi (3.38 mL, 8.46 mmol, 2.5 M in Et20) were 
added via syringe. The reaction was allowed to warm to room temperature and stirred for 
one hour. Over this time the color of the solution changed from red to yellow. The 
solution was recooled and .95 equivalents of W(NPh)CU(OEt2) (2.02 g, 4.10 mmol) in a 
25 mL Et20 solution were added. The reaction was allowed to warm to room temperature 



80 

and was stirred for 6 hours. The mixture, which had turned dark red, was filtered through 
a celite pad and was washed with Et20 until colorless. The solvent was removed under 
reduced pressure and dried for 4 hours. The solid was then washed 3 times with 20 mL of 
pentane and dried under reduced pressure overnight. 2.13 grams of a dark red solid were 
isolated; yield, 80.4%. Anal. Calc'd for C22H29N3CI2S12W: C, 40.88; H, 4.52; N, 6.50. 
Found: C, 40.59; H, 4.21; N, 6.19. 

Preparation of WfNPh)Cbr4.5-(CH^ 2 -l-2-(NSiMe2 bC^H 2 1 - 19: 

N,N'-bis(trimethylsilyl)-4,5-dimethyl-l,2-diaminobenzene 6 (1.29 g, 4.70 mmol), 
W(NPh)C14(OEt2) (2.29 g, 4.65 mmol), and n-BuLi (3.76 mL, 9.40 mmol, 2.5 M in in 
Et20)were reacted as described above for 14. 1 .89 g of a red solid were isolated; 64% 
yield. Anal. Calc'd for C2oH3iN 3 Cl2Si 2 W: C, 38.47; H, 5.00; N, 6.73. Found: C, 
38.29; H, 4.78; N, 6.48. 

Preparation g[M^£hiiQ^2^ ) 2UMs^Il^^JS2iE^ 20: 

W(NPh)Cl2[(NSiMe3)2C6H4] 14 (0.50 g, 0.84 mmol) and two equivalents of 
Ag(OS02CF3)2 (0.43 g, 1.68 mmol) were combined in a Schelnk tube and dissolved in 25 
mL of °C Et20. After stirring at room temperature for 8 hours, the Et20 was removed 
under reduced pressure. The solid was extracted with Et20 and filtered through Celite until 
colorless. The reddish solution was concentrated to 10 mL and cooled to -10 °C to give 
0.59 grams of 20 as an orange solid, yield: 85.0%. 

Preparation of WCNPrnChCPMe^WNSiMe VbC^Ha l. 21: 

W(NPh)Cl2[(NSiMe3)2C<sH 4 ] 14 (0.68 g, 1.14 mmol) was slurried in 30 mL of 
pentane. Excess PMe3 (4.55 mL, 2.00 mmol, .44 M in toluene) was added to the reaction. 
The reaction immediately turned from redish to deep purple. The reaction was cooled to 
-78 °C to give 21 as 0.71 grams of purple crystals, yield; 90.5%. 



81 



Preparation of WfNPh^CblLWNSiMeV bC^Pkl, 
L = THF. 22: 3-Picoline. 23; CPhCN. 2~4: 



W(NPh)Cl2[(NSiMe3)2C6H4] 14 was dissolved in a minimum amount of the 
solvent, L. The deep purple solution was then added slowly to a stirring pentane solution, 
which immediately turned purple. The solutions were then cooled to -78 °C to give purple 
crystals of the mono-adduct. 

Preparation of WfNPh)( , CH 2 C('CH2 ^') 2 r( ' NSiMe ^ 2 c 6 H i" 1 - 25: 

W(NPh)Cl2[(NSiMe 3 ) 2 C6H4] (2.78g, 4.66 mmol) was dissolved in 30 mL of 
Et20 and cooled to -78 °C. Two equivalents of ClMgCH2C(CH 3 ) 3 (7.37 mL, 9.32 mmol, 
1.27 M soln in Et20) were then added. The reaction was allowed to warm to room 
temperature after 30 minutes. After one hour, solvent was removed under reduced 
pressure. The solid was extracted with pentane until clear and filtered through a Celite pad. 
The solution was concentrated to a total volume of about 10 mL and cooled in an -78 °C 
cold bath to yield dark crystals of 25; 2. 19 g (yield 70.1%). Anal. Calc'd for 
C28H47N 3 Si 2 W: C, 50.52; H, 7.12; N, 6.31. Found: C, 50.36; H, 7.04; N, 6.14. 

Preparation of Wf^h^C^CfCH^Phb^NSiMe^ C^PU l. 26: 

W(NPh)Cl 2 [(NSiMe 3 ) 2 C6H4] (2.04 g, 3.42 mmol) was dissolved in 30 mL of 
Et 2 and cooled to -78 °C. Two equivalents of ClMgCH 2 C(CH 3 ) 2 Ph (6.55 mL, 6.84 
mmol, 1.045 M soln in Et 2 0) were then added. The reaction was allowed to warm to room 
temperature after 30 minutes. After one hour, solvent was removed under reduced 
pressure. The solid was extracted with pentane until clear and filtered through a Celite pad. 
The solution was concentrated to a total volume of about 15 mL and cooled in an -78 °C 
cold bath to yield 2.21 g of 26 as a light brown solid. Yield: 82.4%. Anal. Calc'd for 
C 38 H4 5 N 3 Si2W: C, 58.23; H, 5.79; N, 5.36. Found: C, 57.95; H, 5.58; N, 5.29. 



82 



Preparation of WfNPh^CH^WfNSiMe^ CjJU l. 27: 

W(NPh)Cl2[(NSiMe3) 2 C6H 4 ] (1.03 g, 1.73 mmol) was dissolved in 20 mL of 
Et20 and cooled to -78 °C. Two equivalents of MeLi (2.47 mL, 3.46 mmol, 1.4 M soln in 
Et20) were then added. The reaction was allowed to warm to room temperature after 15 
minutes. After 30 minutes, solvent was removed under reduced pressure. The solid was 
extracted with pentane until clear and filtered through a Celite pad. The solution was 
concentrated to a total volume of about 5 mL and cooled in an -78 °C cold bath to yield 680 
mg of 27 as a gold-brown solid. Yield: 70.8%. Anal. Calc'd for C20H33N3S12W: C, 
43.24; H, 5.99; N, 7.56. Found: C, 42.89; H, 5.94; N, 7.29. 

Preparation of WfNPhKCH^CH^^NSiMe^ C^U L 28: 

W(NPh)Cl2[(NSiMe3)2C6H4] (1.12 g, 1.88 mmol) was dissolved in 25 mL of 
Et20 and cooled to -78 °C. Two equivalents of EtMgCl (1.88 mL, 3.76 mmol, 2.0 M soln 
in Et20) were then added. The reaction was allowed to warm to room temperature after 15 
minutes. After 30 minutes, solvent was removed under reduced pressure. The solid was 
extracted with pentane until clear and filtered through a Celite pad. The solvent was 
removed under reduced pressure to yield 0.98 g of 28 as a thick red oil.. Yield: 89.3%. 

Preparation of WfNPhVCfoPhbrfNSiMe VbCfiH ^. 29: 

W(NPh)Cl2[(NSiMe3)2C6H4] 14 (2.02 g, 3.39 mmol) was dissolved in 25 mL of 
Et20 and cooled to -78 °C. Two equivalents of ClMgCH 2 Ph (6.77 mL, 6.77 mmol, 1.0 M 
soln. in Et20) were then added. The reaction was allowed to warm to room temperature 
after 15 minutes. After 30 minutes, solvent was removed under reduced pressure. The 
solid was extracted with pentane until clear and filtered through a Celite pad. The solution 
was concentrated to 10 mL and cooled to -78 °C to give 1.47 grams of 29 as a dark solid. 



83 

Yield: 61.3%. Anal. Calc'd for C32H4iN 3 Si 2 W: C, 54.31; H, 5.84; N, 5.94. Found: C, 
53.98; H, 5.61; N, 5.69. 

Preparation of WfNPh^CnrCHoCMe^WNSiMe^ bCfiH^ I. 33: 

W(NPh)Cl2[(NSiMe3)2C 6 H4] 14 (1.65 g, 2.77 mmol) was dissolved in 25 mL of 
Et20 and cooled to -78 °C. One equivalent of ClMgCH2CMe3 (2.31 mL, 2.77 mmol, 1.2 
M soln in Et20) was then added. The reaction was allowed to warm to room temperature 
after 15 minutes. After 45 minutes, solvent was removed under reduced pressure. The 
solid was extracted with pentane until clear and filtered through a Celite pad. The solution 
was concentrated to 5 mL and cooled to -78 °C to give 1.09 grams of 33 as a red solid. 
Yield: 62.3%. Anal. Calc'd for C23H38N3CIS12W: C, 43.71; H, 6.06; N, 6.65. Found: 
C, 43.38; H, 5.81; N, 6.09. 

Preparation of W^h^CHCMe ^ ^PMe^WNSiMe^ CAH ^. 3 6 : 

In a 200 mL glass tube fitted with a teflon Young's joint, 
W(NPh)(CH2CMe3)2[(NSiMe3)2C 6 H 4 ] (1.25 g, 1.87 mmol) was dissolved in 25 mL of 
toluene. Five equivalents of PMe3 (.968 mL, 9.35 mmol) were then added and the tube 
was sealed. The reaction was then heated to 70 °C for 24 hours. The solution was 
transferred to a round-bottom Schlenk were solvent was removed under reduced pressure. 
The brown oil was extracted with pentane and the volume of the filtrate was concentrated to 
about 15 mL. The solution was cooled to -10 °C to yield 0.83 g of 36 as orange crystals; 
yield 66.0%. Anal. Calc'd for C26H4 6 N 3 PSi2W: C, 46.49; H, 6.90; N, 6.26. Found: 
C, 46.23; H, 6.81; N, 6.05. 

Preparation of WfNPhUCH^Bu)C(Ph)C(Phm(Me3_SiN)9 CAH4[ 38 

W(NPh)(CHCMe3)(PMe 3 )[(NSiMe3)2C6H4] 36 (0.21 g, 0.31 mmol) and 
diphenylacetylene (0.06 g, 0.34 mmol) were dissolved in 25 mL of pentane. The reaction 



84 

was then refluxed for 20 hours. Upon cooling, solvent was stripped in vacuo to give a red 
oil which appeared pure by l H NMR. 

Preparation of WfNPhVHbfPMe V bfTMSTjdaV 39: 

Method 1: 

In a glass tube with a Teflon Young's joint, W(NPh)(CH 2 CMe 3 ) 2 (TMS2pda) (1.66 
g, 2.48 mmol), 25 was dissolved in 25 mL of hexanes. PMe3 (0.64 mL, 6.20 mmol) 
was added via syringe. The solution was then placed in liquid nitrogen while a vacuum 
was applied. Once the solution was frozen solid under vacuum, the flask was sealed. 
Hydrogen gas was then purged through the neck of the flask. Once the neck was purged, 
the H 2 hose was wired securely to the flask. The flask was opened until the H 2 reached a 
pressure of 10 PSI. The flask was then resealed and the H 2 line removed. The reaction 
was then allowed to warm to room temperature. After four hours of stirring, the color of 
the solution changed from brown to magenta. Magenta crystals had also precipitated from 
solution. The solution was transferred to a Schlenk tube and cooled to -10 °C to give 
magenta crystals. The mother liquors were concentrated and cooled to give more of the 
same. Total Yield of 39: 1.48 g (87.8%). Anal Calcd for C24H47N3P 2 Si 2 W: C, 42.41; 
H, 6.97; N, 6.18. Found: C, 42.18; H, 6.79; N, 6.03. 

Method 2: 

W(NPh)Cl 2 (TMS 2 pda) (1.08 g, 1.81 mmol), 14 was dissolved in 20 mL of Et 2 
and cooled to -78 °C in an isopropanol/dry ice bath. Two equivalents of PMe3 (0.38 mL, 
3.62 mmol) were added via syringe. Two equivalents of LiBEt3H (3.62 mL, 3.62 mmol, 
1.0 M solution in THF) were added slowly. After warming to room temperature and 
stirring for four hours, the solvent was removed under reduced pressure. The solid was 
extracted twice with 10 mL of pentane. The brown solution was concentrated to 5 mL and 



85 

cooled to -10 °C. 0.87 g of a brown-red solid precipitated from solution. l B. NMR 
confirmed the formation of 39 with about 15% BEt3 impurity present. 

Method 3: 

W(NPh)(CHCMe 3 )(PMe3)(TMS 2 pda) 36 (50 mg, 0.07 mmol) was dissolved in 
C6D6 in a NMR tube fitted with a teflon Young's joint. One equivalent of PMe3 (7 |iL, 
0.07 mmol) was added via microliter syringe. The NMR tube was then fitted with a 
Schlenk adapter. The NMR tube was frozen in liquid nitrogen and placed under vacuum. 
The tube was then sealed frozen, under vacuum. Hydrogen gas was then purged through 
the Schlenk adapter for five minutes. The teflon seal was opened to allow the H2 to fill the 
vacuum in the NMR tube. The NMR tube was charged with about 15 PSI of H2. Over a 
period of less than 2 hours, complete conversion of 36 to 39 was observed in the *H 
NMR. 

Preparation of WfNPtOfHbfDPPE'KTMS^pdaV 42: 

In a glass tube with a Teflon Young's joint, W(NPh)(CH 2 CMe3)2(TMS2pda) (0.65 
g, 0.98 mmol) and DPPE (0.39 g, 0.98 mmol) were dissolved in 30 mL of hexanes. The 
solution was then placed in liquid nitrogen while a vacuum was applied. H2 gas was 
introduced as described for 39. The reaction was then allowed to warm to room 
temperature. After eight hours of stirring, the color of the solution had changed from 
brown to purple. Purple solid had also precipitated from solution. The solution was 
transferred to a Schlenk tube, concentrated to 10 mL, and cooled to -10 °C to give a purple 
solid. Total Yield: 0.71 g (78.2%). Anal. Calcd. for C44H53N3S12P2W: C, 57.08; H, 
5.77; N, 4.54. Found: C, 57.33; H, 5.84; N, 4.54. 



86 

Preparation of WfNPhXr^ -CoHA KPMe^TMSopda). 46: 

In a glass tube with a Teflon Young's joint, W(NPh)(H) 2 (PMe3)2(TMS2pda), 39, 
(0.64 g, 0.94 mmol) was dissolved in 20 mL of pentane. The solution was then placed in 
liquid nitrogen under vacuum. Once the solution was frozen solid under vacuum, the flask 
was sealed. Ethylene was purged through the neck of the flask and then the hose was 
wired on. The flask was opened to a low pressure of ethylene (2 PSI) for about ten 
seconds. Then flask was then resealed and allowed to warm to room temperature. After 
12 hours, the color of the solution had lightened. The solution was transferred to a 
Schlenk tube and cooled to -10 °C. Purple-brown solid formed and was isolated. The 
mother liquors were reduced in volume under reduced pressure to about 5 mL and recooled 
to yield more solid. Total yield; 0.59 grams, 89.1%. Anal. Calcd. for C26H49N 3 Si2P2W: 
C, 44.25; H, 7.00; N, 5.95. Found: C, 43.91; H, 6.79; N, 5.78. 

Polymerization Experiments: 

All of the ROMP experiments were carried out under an inert atmosphere in 
deolifinated toluene solutions. The reactions were terminated by transfering the mixtures to 
stirring methanol with a trace of BHT added to insure against radical reations upon 
precipitation. The precipitated polymers were dried in vacuo and analyzed by GPC. 



APPENDIX A 
TABLES OF SPECTROSCOPIC DATA 



Table A-l.lHNMR Data 

compound 
l,2-[(CH3)3SiNH] 2 C 6 H4 1 



l,2-Li 2 [(CH3)3SiN] 2 C6H4 2 



l,2-[(CH 3 )2PhSiNH] 2 C6H4 3 



l,2-[(CH 3 )Ph 2 SiNH] 2 C6H4 4 



4,5-Me 2 -l,2-(Me 3 SiNH) 2 C6H4 6 



l,8-(Me3SiNH) 2 CioH 6 7 



l,2-Ph[(CH3) 3 SiNH]C 6 H4 8 



l,2-0PrNH) 2 C 6 H 4 9 



Spectroscopic Data 








5, ppm 


mult 


J, Hz 


int 


assignt 


0.18 


S 




18 


-SiMe3 


3.00 


br s 




2 


-NH 


6.83 


m 




2 


aromatic 


6.89 


m 




2 




0.22 


s 




18 


-SiMe.3 


6.59 


m 




2 


aromatic 


6.87 


m 




2 


aromatic 


0.33 


s 




12 


-SiMe?Ph 


3.28 


brs 




2 


-NH 


6.69 


m 




2 


aromatic 


6.88 


m 




2 


aromatic 


7.20 


m 




6 


aromatic 


7.57 


m 




4 


aromatic 


0.61 


s 




6 


-SiMePh 2 


3.57 


brs 




2 


-NH 


6.58 


m 




2 


aromatic 


6.92 


m 




2 


aromatic 


7.18 


m 




12 


aromatic 


7.58 


m 




8 


aromatic 


0.19 


s 




18 


-SiMe3 


2.12 


s 




6 


4,5-Me 2 


2.95 


br s 




2 


-NH 


6.80 


s 




2 


aromatic 


0.17 


s 




18 


-SiMe3 


5.38 


brs 




2 


-NH 


6.70 


d 


7 


2 


p-CioHg 


7.19 


t 


8 


2 


m-CioHe 


7.33 


d 


7 


2 


0-C10H6 


0.11 


s 




9 


-SiMe 3 


4.09 


br s 




1 


-NH 


4.43 


br s 




1 


-NH 


6.49 


d 


8 


2 


aroamtic 


6.73 


t 


8 


2 


aromatic 


6.96 


t 


8 


2 


aromatic 


7.07 


m 




3 


aromatic 


0.98 


d 


6 


12 


-CHMe? 


3.08 


br s 




2 


-NH 


3.32 


quin 


6 


2 


-CHMe 2 


6.69 


m 




2 


aromatic 


6.93 


in 




2 


aromatic 



88 



89 



l,2-[N(H)C(Me) 2 CH 2 CH(Me)N(H)]- 
C 6 H 4 10 



l,8-[N(H)C(Me) 2 N(H)]CioH 4 11 



W(0)Cl 2 [(Me 3 SiN)2C6H4] 13 



W(NPh)Cl 2 [(Me 3 SiN) 2 C 6 H 4 ] 14 



W(NPh)Cl 2 [(Me 2 PhSiN) 2 C 6 H4] 15 



W(NPh)Cl 2 [l,8-(Me3SiN)2CioH 6 ] 18 



W(NPh)Cl 2 [4,5-Me 2 -l,2- 
(Me 3 SiN) 2 C6H4] 19 



0.83 


d 


6 


3 


-CHMe 


0.89 


s 




3 


-CMe(Me) 


1.07 


s 




3 


-CMe(Me) 


1.25 


dd 


6 


1 


-CHH 


1.62 


t 


6 


1 


-CHH 


2.90 


br s 




2 


-NH 


3.17 


qd 


4 


1 


-CHMe 


6.45 


m 




2 


aromatic 


6.80 


m 




2 


aromatic 


0.98 


s 




6 


-CMe? 


3.42 


br s 




2 


-NH 


6.26 


d 


7 


2 


aromatic 


7.23 


d 


7 


2 


aromatic 


7.35 


t 


7 


2 


aromatic 


0.39 


s 




18 


-SiM£3 


6.80 


m 




2 


aromatic 


6.95 


in 




2 




0.35 


s 




18 


-SiMe 3 


6.71 


t 


8 


1 


p-NPh-H 


6.94 


m 




2 


aromatic 


7.01 


t 


8 


2 


m-NPh-H 


7.14 


m 




2 


aromatic 


7.31 


d 


8 


2 


o-NPh-H 


0.62 


s 




6 


-SiMe?Ph 


0.68 


s 




6 


-SiMe 2 Ph 


6.62 


m 




2 


aromatic 


6.65 


t 


8 


1 


p-NPh-H 


6.92 


t 


8 


2 


m-NPh-H 


7.02 










to 








aromatic 


7.47 










0.41 


s 




18 


-SiMe 3 


6.39 


d 


7 


2 


P-C10H6 


6.72 


t 


8 


1 


p-NPh-H 


6.93 


d 


7 


2 


0-C10H6 


6.98 


t 


8 


2 


m-NPh-H 


7.13 


t 


7 


2 


m-CioH 6 


7.48 


d 


8 


2 


o-NPh-H 


0.41 


s 




18 


-SiMe 3 


1.99 


s 




6 


4,5-Me9Ph 


6.73 


t 


8 


1 


p-NPh-H 


7.02 


t 


8 


2 


m-NPh-H 


7.07 


s 




2 


aromatic 


7.35 


d 


8 


2 


o-NPh-H 



90 



W(NPh)(OS02CF3)2[(Me 3 SiN)2C6H 4 ]- 
(OEt 2 ) 20 



0.32 



18 -SiMg3 





1.09 


t 


7 


6 


-OEt2 




3.25 


q 


7 


4 


-OEts 




6.55 


t 


8 


1 


p-NPh-H 




7.02 


t 


8 


2 


m-NPh-H 




7.09 


m 




2 


aromatic 




7.30 


m 




2 


aromatic 




7.38 


d 


8 


2 


o-NPh-H 


W(NPh)Cl2(PMe3)[(Me 3 SiN)2C 6 H4] 


0.42 


s 




18 


-SiMs3 


21 














0.79 


d 


JVh=9 


9 


-PMe 3 




6.63 


t 


8 


1 


p-NPh-H 




6.83 


m 




2 


aromatic 




7.01 


IT) 




2 


aromatic 




7.17 


t 


8 


2 


m-NPh-H 




7.49 


d 


8 


2 


o-NPh-H 


W(NPh)Cl2(THF)[(Me 3 SiN)2C6H 4 ] 22 


0.41 


s 




18 


-SiMe 3 




0.92 


qnt 


3 


4 


-THF 




3.63 


t 


6 


4 


-THF 




6.62 


t 


8 


1 


p-NPh-H 




6.85 


m 




2 


aromatic 




7.03 


m 




2 


aromatic 




7.10 


t 


8 


2 


m-NPh-H 




7.47 


d 


8 


2 


o-NPh-H 


W(NPh)Cl 2 (3-Me-py)[(Me3SiN) 2 C6H4] 


0.42 


s 




18 


-SiMe 3 


23 














2.17 


s 




3 


py-Me 




6.21 


t 


2 


1 


py-5-H 




6.33 


d 


8 


1 


py-4-H 




6.54 


m 




2 


aromatic 




6.65 


t 


11 


1 


p-NPh-H 




6.76 


m 




2 


aromatic 




7.18 


t 


9 


2 


m-NPh-H 




7.61 


d 


7 


2 


o-NPh-H 




8.72 


s 




1 


py-l-H 




8.75 


d 


6 


1 


py-6-H 


W(NPh)Cl 2 (NCCH3)[(Me3SiN)2C 6 H4] 


0.38 


s 




18 


-SiMs3 


24 














0.49 


s 




3 


-NCCMe 




6.67 


t 


7 


1 


p-NPh-H 




6.93 


m 




2 


aromatic 




7.04 


t 


7 




m-NPh-H 




7.14 


m 




2 


aromatic 




7.34 


d 


7 


2 


o-NPh-H 


W(NPh)(CH 2 CMe3)2[(Me 3 SiN)2- 


0.54 


s 




18 


-SiMS3 


C 6 H 4 ] 25 














1.00 


s 




18 


-CMe 3 



91 



W(NPh)(CH 2 CMe2Ph)2[(Me 3 SiN)2- 
C 6 H 4 ] 26 



W(NPh)(CH3)2[(Me 3 SiN)2C 6 H4l 27 



W(NPh)(CH 2 CH3)2[(Me3SiN)2C 6 H4] 
28 



W(NPh)(CH 2 Ph)2[(Me3SiN)2C 6 H 4 ] 29 



2.13 


d 


10 

J 2 WH=H 


2 


-CH 2 CMe3 


2.29 


d 


10 

J 2 WH=H 


2 


-CH 2 CMe 3 


6.83 


t 


7 


1 


p-NPh-H 


6.86 


m 




2 


aromatic 


7.19 


t 


7 


2 


m-NPh-H 


7.25 


m 




2 


aromatic 


7.59 


d 


7 


2 


o-NPh-H 


0.42 


s 




18 


-SiMe 3 


1.37 


s 




9 


-CMe?Ph 


1.38 


s 




9 


-CMS2Ph 


1.95 


d 


11 

J 2 WH=H 


2 


-CH2C 


2.94 


d 


11 

J 2 WH=H 


2 


-CH2C 


6.83 


t 


7 


1 


aromatic 


6.94 


t 


7 


2 




6.97 


m 




2 




7.01 


t 


7 


4 




7.06 


t 


7 


2 




7.18 


d 


7 


4 




7.19 


d 


7 


2 




7.30 


m 




2 




0.31 


s 




18 


-SiMe3 


1.12 


s 


J 2 W-H=6 


6 


W-Me 


6.86 


t 


8 


1 


p-NPh-H 


7.06 


m 




2 


aromatic 


7.11 


t 


8 


2 


m-NPh-H 


7.32 


d 


8 


2 


o-NPh-H 


7.35 


m 




2 


aromatic 


0.29 


s 




18 


-SiMS3 


1.86 


s 




6 


-CH2CH3 


1.91 


m 




2 


-CH2CH3 


2.31 


m 




2 


-CH2CH3 


6.86 


t 


8 


1 


p-NPh-H 


7.04 


m 




2 


aromatic 


7.11 


t 


8 


2 


m-NPh-H 


7.31 


d 


8 


2 


o-NPh-H 


7.37 


m 




2 


aromatic 


0.09 


s 




18 


-SiMe 3 


2.78 


s 




4 


-CH2Ph 


6.81 


t 


8 


2 


p-CH 2 Ph-H 


6.88 


t 


8 


1 


p-NPh-H 


7.04 










to 








aromatic 


7.19 










7.30 


d 


8 


2 


o-NPh-H 



92 





7.37 


in 




2 


aromatic 


spectrum taken at +80 °C in C7D8 














2.71 


m 


7 


4 


— c 


W(NPh)Ph2[(Me3SiN)2C 6 H 4 ] 30 


0.11 


s 




18 


-SiMe 3 




6.82 


t 


7 


2 


aromatic 




6.86 


t 


7 


1 






7.04 


t 


7 


4 






7.18 


t 


7 


2 






7.21 


m 




2 






7.39 


m 




2 






7.52 


d 


7 


2 






7.62 


d 


7 


4 




W(NPh)(CH 2 CMe 3 )2- 












[(Me2PhSiN) 2 C6H4] 31 


0.81 


s 




12 


-SiMe 2 Ph 




1.03 


s 




18 


-CH 2 CMe 3 




2.04 


d 


10 

Pwh-11 


2 


-CH 2 CMe 3 




2.78 


d 


10 

J 2 WH=H 


2 


-CH 2 CMe 3 




6.59 








aromatic 




to 












7.68 










W(NPh)Cl(CH 2 CMe 3 )[(Me 3 SiN) 2 - 


0.24 


s 




9 


-SiMe 3 


C 6 H 4 ] 33 














0.42 


s 




9 


-SiMe 3 




1.23 


s 




9 


-CH 2 CMe 3 




1.93 


d 


10 


1 


-CH9CMe 3 




2.08 


d 


10 


1 


-CH 2 CMe 3 




6.76 


t 


7 


1 


p-NPh-H 




6.94 












to 








aromatic 




7.24 












7.41 


d 


8 


2 


o-NPh-H 


W(NPh)(CH 2 CMe3)(NMe2)[(Me 3 SiN)2 


0.31 


s 




9 


-SiMe 3 


C 6 H 4 ] 34 














0.46 


s 




9 


-SiMe 3 




1.03 


s 




9 


-CH 2 CMe 3 




1.33 


d 


10 


1 


-CH2CMe 3 




2.60 


d 


10 


1 


-CH2CMe 3 




3.19 


s 




3 


-NMe2 




3.68 


s 




3 


-NMS2 




6.72 












to 








aromatic 




7.28 










W(NPh)(CH 2 C(Me) 2 CH 2 )- 












[(Me 3 SiN)2C6H4] 35 


-1.70 


d 


9 


2 


-CH 2 




0.39 


s 




9 


-SiMe 3 




0.54 


s 




3 


-CH 2 CMe9- 




0.57 


s 




3 


-CH 2 CMe?- 



93 





1.24 


s 




9 


-SiMe3 




2.11 


d 


9 


2 


-CH2 




6.75 












to 








aromatic 




7.59 










W(NPh)(CHCMe3)(PMe3)- 


0.38 


s 




9 


-SiM£3 


[(Me 3 SiN) 2 C6H4] 36 














0.41 


s 




9 


-SiMe 3 




0.98 


d 


2 Jp-h=9 


9 


-PMS3 




1.39 


s 




9 


-CM£3 




6.68 












to 












7.13 






9 


aromatic 


W(NPh)[CH(r-Bu)C(Ph)C(Ph)]- 












[(Me 3 SiN)2C6H4] 38 


-0.08 


s 




9 


-SiMe 3 




0.43 


s 




9 


-SiMe3 




1.38 


s 




9 


-r-Bu 




2.81 


s 


2 Jw-h = 8 


1 


-C-H 




6.62 












to 








aromatic 




7.64 










W(NPh)(H)2(PMe3)2[(Me3SiN) 2 C 6 H4] 


0.79 


s 




9 


-SiMe.3 


39 














0.81 


s 




9 


-SiMe^ 




1.04 


s 




18 


-PM§3 




6.80 












to 








aromatic 




7.45 












9.28 


t 


J = 38 


2 


W-H 


Spectrum in C7D8 at -50 °C 


0.69 


s 




9 


-SiMe 3 




0.75 


s 




9 


-SiMe3 




0.84 


t 


J2 P .H=3 


18 


-PMes 




6.74 












to 








aromatic 




7.38 












9.00 


m 






W-H 


W(NPh)(H) 2 (PMe2Ph) 2 - 












[(Me 3 SiN)2C6H4] 40 


0.53 


s 




18 


-SiMe 3 




1.22 


s 




6 


-PMe?Ph 




6.72 












to 








aromatic 




7.29 












9.63 


br s 




2 


W-H 


Spectrum in C7D8 at -50 °C 


0.53 


s 




9 


-SiMe 3 




0.59 


s 




9 


-SiMe3 




1.19 


t 


Jp-H = 4 


12 


-PMe2Ph 




9.56 


t 


J = 40 


2 


W-H 



94 



W(NPh)(H) 2 (PCy3)[(Me3SiN)2C 6 H4] 
41 



W(NPh)(H)2DPPE[(Me 3 SiN)2C 6 H4] 
42 



W(NPh)(H)(CH 2 CMe 3 )- 
[(Me3SiN)2C6H4] 44 



W(NPh)(T!2-C2H4)(PMe3)2- 
[(Me 3 SiN)2C 6 H4] 46 

spectrum taken at -25 °C 



W(NPh)(T! 2 -CH2CHPh)(PMe 3 )2- 
[(Me 3 SiN) 2 C 6 H4] 47 



0.81 
1.04 


s 




18 


-SiMe 3 


to 
1.93 


m's 




11 


P£*3 


6.81 


t 


7 


1 


p-Ph-H 


6.95 


m 




2 


aromatic 


6.99 


t 


7 


2 


m-Ph-H 


7.18 


d 


7 


2 


o-Ph-H 


7.47 


m 




2 


aromatic 


0.49 


s 




18 


-SiMe 3 


2.23 
2.42 
6.72 


m 
m 
m 




2 
2 
2 


PCH2CH2P 
PCH2CH2P 
aromatic 


6.76 


m 


8 


4 


aromatic 


6.94 


m 




2 




6.98 










to 










7.18 


m 








7.69 


t 


8 


4 


aromatic 


10.33 


d 


J = 23 


1 


W-H 


10.62 


d 


J = 23 


1 


W-H 


0.34 
0.42 
0.94 
2.71 
3.21 
6.79 


s 
s 
s 
d 
br s 


7 


9 
9 
9 

1 
1 


-SiMe 3 

-SiMe 3 

-CH 2 CMe 3 

-CH 2 CMe 3 

-CH 2 CMe 3 


to 








aromatic 


7.59 










18.48 


s 


1 J W -H=156 


1 


W-H 


0.37 
0.65 
1.03 


s 
s 
s 




9 
9 
18 


-SiMe 3 
-SiMe 3 
-PM© 


1.91 
2.09 
6.61 


m 
m 




2 

2 


C2H4 
C2H4 


to 








aromatic 


7.42 










0.41 


s 




18 


-SiMe 3 


0.86 
2.62 
2.80 
3.87 


d 

m 

m 

t 


8 


3 
1 
1 
1 


-PMe3 
-QfcCHPh 
-OfeGHPh 
-CHoCHPh 



95 



6.41 

to aromatic 

7.24 



Table A-2. 12c NMR Data 



96 



coumpound 
l,8-(Me 3 SiNH)2CioH 6 7 


5, ppm 

0.80 

116.13 


mult 

s 
s 




121.22 


s 




122.21 


s 




125.99 


s 




138.15 


s 




144.60 


s 


l,2-(iPrNH) 2 C6H 4 9 


23.2 
44.6 


s 
s 




114.2 


s 




119.8 


s 




137.7 


s 


l,2-[N(H)C(Me) 2 CH 2 CH(Me)N(H)l- 
C 6 H 4 10 


23.9 
26.9 


s 
s 




32.8 


s 




48.1 


s 




51.6 


s 




52.0 


s 




119.6 


s 




120.9 


s 




121.6 


s 




121.8 


s 




138.2 


s 




141.6 


s 


l,8-[N(H)C(Me) 2 N(H)]Ci H 4 11 


28.1 
63.8 


s 
s 




105.6 


s 




111.3 


s 




117.0 


s 




127.1 


s 




135.2 


s 




140.6 


s 


WOCl 2 [(Me 3 SiN) 2 C6H4] 13 


0.02 
121.09 


s 
s 




129.18 


s 




132.43 




W(NPh)Cl 2 [(Me 3 SiN) 2 C 6 H 4 ] 14 


0.6 
122.0 


s 
s 




126.1 


s 




128.1 


s 




128.5 


s 




128.6 


s 




130.8 


s 



Jch, Hz 



assignmt 

-SiMe 3 

aromatic 



-NCHMe? 
-NCHMe 2 

aromatic 



NC(Me) 2 N 
NC(Me) 2 N 



-SiMe 3 



-SiMe 3 
aromatic 



97 



W(NPh)Cl2[l,8-(Me3SiN) 2 CioH 6 ] 18 


3.13 


s 


-SiMe 3 




121.31 


s 


aromatic 




125.72 


s 






127.31 


s 






127.67 


s 






128.41 


s 






129.32 


s 






138.13 


s 






140.86 


s 




W(NPh)Cl 2 [4,5-Me 2 -l,2- 








(Me 3 SiN)2C 6 H4] 19 


1.98 


s 


-SiMe 3 




19.87 


s 


4,5-Ph-ft 




122.32 


s 


aromatic 




124.67 


s 






126.43 


s 






128.76 


s 






133.32 


s 






142.12 


s 






148.98 


s 




W(NPh)Cl2(PMe3)[(Me 3 SiN)2C 6 H4] 








21 


1.99 


s 


-SiMe 3 




11.64 


d 


1 Jc-p = 21 -PMe 3 




120.94 


s 


aromatic 




122.99 


s 






127.03 


s 






127.29 


s 






128.35 


s 






145.41 


s 




W(NPh)Cl2(THF)[(Me 3 SiN)2C6H 4 ] 22 


1.50 


s 


-SiMe 3 




25.05 


s 


THF 




70.07 


s 


THF 




120.41 


s 


aromatic 




124.10 


s 






126.64 


s 






128.25 


s 






128.57 


s 






144.12 


s 






154.09 


s 




W(NPh)Cl 2 (3-Me-Py)- 








[(Me 3 SiN)2C 6 H4] 23 


1.69 


s 


-SiMe 3 




17.70 


s 


3-Me-py 




119.92 


s 


aromatic 




122.61 


s 






123.16 


s 






127.03 


s 






127.91 


s 






128.15 


s 






128.55 


s 






132.81 


s 





98 





137.86 


s 








147.12 


s 








148.83 


s 








152.51 


s 






W(NPh)(CH 2 CMe3)2[(Me3SiN)2C 6 H4l 


4.4 


s 




-SiMS3 


25 












34.8 


s 




-CMS3 




38.3 


s 




-CMe 3 




90.8 


s 


123 


-CH 2 CMe 3 




118.9 


s 




aromatic 




119.3 


s 








126.0 


s 








128.5 


s 








129.2 


s 








144.2 


s 








155.8 


s 






W(NPh)(CH 2 CMe 2 Ph)2- 


4.1 


s 




-SiM£3 


[(Me 3 SiN)2C6H4] 26 












32.5 


s 




-CMe?Ph 




35.9 


s 




-CMe?Ph 




44.2 


s 




-CMe 2 Ph 




93.1 


s 


126 


-CH 2 CMe 2 Ph 




119.4 


s 




aromatic 




119.8 


s 








125.5 










125.6 










126.1 










128.2 










128.4 










129.2 










143.8 










153.4 










155.2 








W(NPh)(CH 3 )2[(Me3SiN)2C6H 4 ] 27 


2.3 


s 




-SiMe3 




41.2 


s 


123 


-CH3 




122.4 


s 




aromatic 




124.8 


s 








125.2 


s 








125.8 


s 








128.7 


s 








129.8 


s 








131.2 


s 






W(NPh)(CH2CH 3 )2[(Me3SiN)2C 6 H 4 ] 










28 


1.5 


s 




-SiMe 3 




17.4 


s 




-CH2CH 3 




58.4 


s 


120 


-CH2CH3 




122.3 










123.9 










125.0 










125.6 









99 



W(NPh)(CH 2 Ph)2[(Me3SiN)2C 6 H4] 29 



W(NPh)Cl(CH 2 CMe 3 )- 
[(Me3SiN) 2 C6H 4 ] 33 



W(NPh)(CHCMe 3 )(PMe 3 )- 
[(Me 3 SiN) 2 C6H4] 36 



W(NPh)[CH(f-Bu)C(Ph)C(Ph)]- 
[(Me 3 SiN) 2 C 6 H 4 ] 38 



128.8 




135.1 




156.2 




2.10 


s 


66.33 


s 


123.49 


s 


123.78 


s 


125.65 


s 


126.20 


s 


126.51 


s 


127.68 


s 


128.04 


s 


128.42 


s 


128.61 


s 


128.97 


s 


154.20 


s 


1.26 


s 


2.08 


s 


35.13 


s 


36.11 


s 


80.15 


s 


121.7 


s 


122.3 


s 


123.6 


s 


126.1 


s 


127.2 


s 


128.6 


s 


132.0 


s 


136.9 


s 


155.9 


s 


3.4 


s 


4.1 


s 


16.2 


d 


34.9 


s 


45.0 


s 


117.6 


s 


119.3 


s 


122.4 


s 


123.6 


s 


124.7 


s 


128.7 


s 


148.1 


s 


277.4 


s 


1.33 


s 


2.01 


s 


33.81 


s 


38.61 


s 



-StMe 3 
-CH 2 Ph 



121 



-SiMe 3 

-SiMe 3 

-CH 2 CMe 3 

-CiPiCMes 

-CH 2 CMe 3 



-SiMe 3 

-SiMe 3 

-PMe 3 

-CMS3 

-CMe 3 

aromatic 



110 



aromatic 
-CHCMe 3 



-SiMe 3 
-SiMs 3 
-CMs 3 
-CMe 3 



100 



W(NPh)(H) 2 (PMe 3 )2- 
[(Me3SiN)2C6H4] 39 



W(NPh)(Ti 2 -C 2 H4)(PMe 3 )2- 
[(Me 3 SiN)2C6H4] 46 



77.10 


s 


-CH-r-Bu 


90.08 


s 


-CH-r-Bu-CPhCPh 


122.08 


s 




123.09 


s 




123.42 


s 




123.92 


s 




124.68 


s 




124.99 


s 




125.38 


s 




125.91 


s 




126.01 


s 




126.46 


s 




127.00 


s 




128.20 


s 




128.62 


s 




128.78 


s 




128.93 


s 




131.97 


s 




133.15 


s 




133.31 


s 




139.91 


s 




140.03 


s 




147.08 


s 




157.83 


s 




4.92 


s 


-SiMe3 


6.43 


s 


-SiM£3 


15.99 


s 


-PM£3 


115.21 


s 


aromatic 


116.53 


s 




118.17 


s 




119.20 


s 




123.31 


s 




126.71 


s 




128.68 


s 




151.13 


s 




2.67 


s 


-SiMS3 


6.34 


s 


-SiMS3 


15.78 


s 


-PMS3 


38.13 


s 156 


122.23 


s 




123.13 


s 




124.28 


s 




125.51 


s 




127.23 


s 




128.91 


s 




129.23 


s 




129.78 


s 




158.23 


s 





101 

Table A-3. ^IPNMRData 

W(NPh)Cl2(PMe 3 )[(Me3SiN)2C6H4] 21 
W(NPh)(CHCMe3)(PMe3)[(Me3SiN)2C 6 H 4 ]36 
W(NPh)(CHCMe 3 )(PEt3)[(Me3SiN) 2 C 6 H4]37 
W(NPh)(H) 2 (PMe3)2[(Me3SiN) 2 C6H4] 39 
W(NPh)(H)2(PMe2Ph)2[(Me3SiN) 2 C6H 4 ] 40 
W(NPh)(H)2(PCy3)[(Me 3 SiN)2C 6 H4] 41 
W(NPh)(H)2DPPE[(Me 3 SiN)2C 6 H4] 42 



W(NPh)0i2-C2H4)(PMe3)2[(Me3SiN) 2 C 6 H4] 46 -23.30 
spectrum taken in C7D8 at -40 °C -21.61 



-18.22 


br s 




-2.49 


s 


J 1 w-P=128 


-11.42 


br s 




-24.46 


s 


J 1 W_P=188 


-17.43 


s 


J 1 W-P=164 


66.71 


s 


1%-?= 56 


30.43 
-12.70 


d 
d 


J 2 p.p=83 
J 2 P.P=83 


-23.30 
-21.61 


br s 
s 


J 1 W-P=238 



APPENDIX B 
TABLES OF CPvYSTALLOGRAPHJC DATA 




103 



104 



Crvstallographic Data for WfNPrACbrfMe^SiNb CgH/l. 14 



Table B-l. Crvstallographic data for 14. 

A. Crystal data (298 K) 

a, A 

b, A 

c, A 

a, deg. 
P,deg. 
y, deg. 

v,A 3 

dcalc, g cm" 3 (298 K) 

Empirical formula 

Formula wt, g 

Crystal system 

Space group 

Z 

F(000), electrons 

Crystal size (mm 3 ) 

B. Data collection (298 K) 
Radiation, A, (A) 

Mode 
Scan range 

Background 

Scan rate, deg. min." 1 

28 range, deg. 
Range ofhkl 



14 

10.294(2) 
17.859(3) 
13.377(3) 

104.15(2) 

2384.6(8) 

1.661 

Ci8H 2 7N 3 Si2Cl2W 

596.36 

Monoclinic 

P2i/n 

4 

1168 

0.14x0.21x0.11 



Mo-K a , 0.71073 

co-scan 

Symmetrically over 1.2° 
about K a i2 maximum 

offset 1.0 and -1.0 in co from 
K a i ) 2 m axmuim 

3-6 



3-55 
< 
< 
-17 < 



h 

k 
I 



< 13 

< 23 

< 17 



Total reflections measured 
Unique reflections 

Absorption coeff. u. (Mo-K a ), mm" 1 
Min. & Max. Transmission 

C. Structure refinement 

S, Goodness-of-fit 

Reflections used, I > 2o~(I) 
No. of variables 
R, wR* (%) 

RinL (%) 
Max. shift/esd 



5770 
5300 
5.18 

0.352, 0.153 



1.73 

2985 

235 

5.83%, 6.12% 

5.63% 

0.0003 



105 



Table B-l. continued. 

min. peak in diff. four, map (e A" 3 ) -2.45 

max. peak in diff. four, map (e A" 3 ) 1.56 

* Relevant expressions are as follows, where in the footnote F and F c represent, 
respectively, the observed and calculated structure-factor amplitudes. 

Function minimized was w(IF l - IF C I) 2 , where w= (g(F))~ 2 

R = I(IIF I-IF C II)/SF I 

wR = [Iw(IF l - IF C I) 2 / IIFqI 2 ] 1 / 2 

S = [Zw(IF l-IF c l) 2 /(m-n)] 1 / 2 



106 



Table B-2: Fractional coordinates and equivalent isotropic^-thermal parameters (A2 ) 



for the 


non-H atoms of compound 14. 






Atom 


X 


v 


z 


U 


W 


0.16873(5) 


0.21558(3) 


0.30838(4) 


0.0439(2) 


Cll 


0.0285(4) 


0.1100(3) 


0.2519(3) 


0.079(2) 


C12 


0.1131(5) 


0.2447(3) 


0.1288(3) 


0.088(2) 


Sil 


0.1700(4) 


0.1558(2) 


0.5550(3) 


0.0543(14) 


Si2 


0.2852(4) 


0.3984(3) 


0.3248(3) 


0.056(2) 


Nl 


0.1191(10) 


0.2080(6) 


0.4397(7) 


0.051(4) 


N2 


0.1783(10) 


0.3226(6) 


0.3385(7) 


0.045(4) 


N3 


0.3280(10) 


0.1796(6) 


0.3214(8) 


0.048(4) 


CI 


0.0275(13) 


0.2686(7) 


0.4272(8) 


0.044(5) 


C2 


0.0602(11) 


0.3307(7) 


0.3721(8) 


0.041(4) 


C3 


-0.0280(12) 


0.3933(8) 


0.3513(9) 


0.049(5) 


C4 


-0.1391(12) 


0.3937(9) 


0.3912(10) 


0.054(5) 


C5 


-0.1708(13) 


0.3330(9) 


0.4451(10) 


0.057(6) 


C6 


-0.0916(13) 


0.2718(9) 


0.4624(9) 


0.057(6) 


C7 


0.4462(12) 


0.1497(8) 


0.3062(10) 


0.051(5) 


C8 


0.4420(13) 


0.1245(8) 


0.2079(11) 


0.054(5) 


C9 


0.556(2) 


0.0924(9) 


0.1887(13) 


0.076(7) 


CIO 


0.672(2) 


0.0858(10) 


0.266(2) 


0.082(8) 


Cll 


0.6756(15) 


0.1119(10) 


0.361(2) 


0.089(8) 


C12 


0.5616(14) 


0.1442(9) 


0.3827(12) 


0.078(7) 


C13 


0.313(2) 


0.0961(10) 


0.5456(12) 


0.092(8) 


C14 


0.032(2) 


0.0939(9) 


0.5689(13) 


0.088(8) 


C15 


0.214(2) 


0.2225(10) 


0.6625(11) 


0.090(7) 


C16 


0.4484(15) 


0.3572(11) 


0.3311(14) 


0.097(9) 


C17 


0.216(2) 


0.4451(10) 


0.1994(11) 


0.080(7) 


C18 


0.298(2) 


0.4619(10) 


0.4354(11) 


0.087(8) 


2For anisotropic 


atoms, the U value 


is U e q, calculated 


as U eq = 1/3 Xilj 


Uy ai* a;* 


Ay where Aj; is 


the dot product of the i tn and j tn direc 


t space unit cell vectors. 



107 
Table B-3: 



1 


2 


3 


1-2 


1-2-3 


Cll 


W 


C12 


2.383(4) 


82.9(2) 


Cll 


W 


Nl 




87.7(3) 


Cll 


w 


N2 




146.8(3) 


Cll 


w 


N3 




102.9(4) 


Cll 


w 


CI 




95.6(3) 


C12 


w 


Nl 


2.387(4) 


150.5(3) 


C12 


w 


N2 




88.9(3) 


C12 


w 


N3 




99.8(4) 


C12 


w 


CI 




120.5(3) 


C12 


w 


C2 




98.2(3) 


Nl 


w 


N2 


1.951(11) 


83.9(4) 


Nl 


w 


N3 




109.5(5) 


Nl 


w 


CI 




32.9(4) 


Nl 


w 


C2 




61.9(4) 


N2 


w 


N3 


1.952(11) 


110.2(5) 


N2 


w 


CI 




61.4(4) 


N2 


w 


C2 




32.4(4) 


N3 


w 


CI 


1.730(10) 


137.4(4) 


N3 


w 


C2 




137.6(4) 


CI 


w 


C2 


2.582(13) 


31.9(4) 


C2 


w 


Cll 


2.582(13) 


117.2(3) 


Nl 


Sil 


C13 


1.768(10) 


108.4(7) 


Nl 


Sil 


C14 




109.4(6) 


C13 


Sil 


C14 


1.85(2) 


107.8(8) 


C13 


Sil 


C15 




112.2(8) 


C14 


Sil 


C15 


1.84(2) 


111.1(8) 


C15 


Sil 


Nl 


1.84(2) 


107.8(7) 


N2 


Si2 


C16 


1.781(12) 


106.0(7) 


N2 


Si2 


C17 




109.0(6) 


C16 


Si2 


C17 


1.82(2) 


111.6(8) 


C16 


Si2 


C18 




109.2(8) 


C17 


Si2 


C18 


1.85(2) 


112.7(8) 


C18 


Si2 


N2 


1.84(2) 


108.0(7) 


CI 


Nl 


W 


1.42(2) 


98.8(7) 


CI 


Nl 


Sil 




123.5(9) 


w 


Nl 


Sil 




137.4(7) 


C2 


N2 


W 


1.40(2) 


99.4(8) 


C2 


N2 


Si2 




124.1(9) 


W 


N2 


Si2 




136.4(6) 


C7 


N3 


W 


1.39(2) 


166.2(9) 


C2 


CI 


C6 


1.42(2) 


118.4(12) 


C2 


CI 


W 




74.1(7) 


C2 


CI 


Nl 




115.0(12) 


C6 


CI 


W 


1.42(2) 


151.9(9) 


C6 


CI 


Nl 




126.6(12) 


W 


CI 


Nl 




48.3(6) 



108 



Table B-3. continued. 



C3 


C2 


w 


1.42(2) 


150.1(8) 


C3 


C2 


N2 




125.3(11) 


C3 


C2 


CI 




119.7(12) 


W 


C2 


N2 




48.2(6) 


W 


C2 


CI 




74.1(8) 


N2 


C2 


CI 




114.9(11) 


C4 


C3 


C2 


1.38(2) 


118.6(13) 


C5 


C4 


C3 


1.38(2) 


121.6(13) 


C6 


C5 


C4 


1.35(2) 


120.9(14) 


CI 


C6 


C5 




120.8(13) 


C8 


C7 


C12 


1.38(2) 


120.5(13) 


C8 


C7 


N3 




116.2(10) 


C12 


C7 


N3 


1.37(2) 


123.3(13) 


C9 


C8 


C7 


1.39(2) 


118.7(12) 


CIO 


C9 


C8 


1.37(2) 


121.(2) 


Cll 


CIO 


C9 


1.34(3) 


120.(2) 


C12 


Cll 


CIO 


1.40(2) 


120.6(14) 


C7 


C12 


Cll 




119.(2) 



109 



Table B-4 


: Anisotropic 


thermal parameters^ for the 


non-H atoms of 


compound 14 




Atom 


Ull 


U22 


U33 


U12 


U13 


U23 
0.0013(3) 


W 


0.0429(3) 


0.0511(3) 


0.0386(3) 


0.0116(3) 


0.0120(2) 


Cll 


0.065(2) 


0.081(3) 


0.091(3) 


-0.011(2) 


0.018(2) 


-0.024(2) 


C12 


0.128(4) 


0.089(3) 


0.042(2) 


0.028(3) 


0.012(2) 


0.004(2) 


Sil 


0.068(3) 


0.048(3) 


0.045(2) 


0.007(2) 


0.010(2) 


0.010(2) 


Si2 


0.045(2) 


0.064(3) 


0.060(2) 


-0.005(2) 


0.019(2) 


0.002(2) 


Nl 


0.058(6) 


0.054(8) 


0.044(6) 


0.007(6) 


0.019(5) 


0.006(5) 


N2 


0.064(7) 


0.038(6) 


0.043(5) 


0.007(5) 


0.029(5) 


0.003(5) 


N3 


0.048(7) 


0.046(7) 


0.053(6) 


0.012(5) 


0.020(5) 


-0.014(5) 


CI 


0.044(7) 


0.053(10) 


0.033(6) 


0.010(6) 


0.004(5) 


-0.005(5) 


C2 


0.038(6) 


0.059(9) 


0.031(5) 


0.006(6) 


0.016(5) 


0.002(6) 


C3 


0.040(7) 


0.058(9) 


0.049(7) 


-0.001(7) 


0.013(6) 


0.009(7) 


C4 


0.038(7) 


0.075(11) 


0.051(7) 


0.005(7) 


0.014(6) 


-0.008(7) 


C5 


0.042(7) 


0.085(12) 


0.046(7) 


-0.004(8) 


0.016(6) 


-0.003(8) 


C6 


0.051(8) 


0.077(12) 


0.041(7) 


-0.010(8) 


0.008(6) 


0.009(7) 


C7 


0.040(7) 


0.045(9) 


0.068(8) 


-0.006(6) 


0.018(6) 


-0.013(7) 


C8 


0.046(8) 


0.049(9) 


0.066(8) 


0.009(7) 


0.014(7) 


0.005(7) 


C9 


0.089(12) 


0.070(12) 


0.088(11) 


0.013(10) 


0.056(10) 


0.003(9) 


CIO 


0.051(10) 


0.065(12) 


0.14(2) 


0.007(9) 


0.033(11) 


0.017(12) 


Cll 


0.039(9) 


0.079(14) 


0.13(2) 


0.003(8) 


-0.020(10) 


-0.009(12) 


C12 


0.058(9) 


0.090(13) 


0.071(9) 


0.019(9) 


-0.014(8) 


-0.029(9) 


C13 


0.113(15) 


0.093(15) 


0.073(11) 


0.038(12) 


0.025(10) 


0.019(10) 


C14 


0.099(13) 


0.054(11) 


0.109(13) 


-0.003(10) 


0.019(11) 


0.038(10) 


C15 


0.120(14) 


0.086(13) 


0.053(8) 


0.018(12) 


-0.003(9) 


-0.017(9) 


C16 


0.064(11) 


0.10(2) 


0.13(2) 


0.025(11) 


0.037(10) 


0.026(13) 


C17 


0.075(11) 


0.085(14) 


0.082(11) 


-0.017(10) 


0.025(9) 


-0.001(10) 


C18 


0.085(12) 


0.084(13) 


0.085(12) 


-0.021(10) 


0.010(9) 


0.000(10) 



2 Uij are the mean-square amplitudes of vibration in A 2 from the general temperature factor expression 
exp[-27c 2 (h 2 a* 2 Ull + k 2 b* 2 U22 + l 2 c* 2 U33 + 2hka*b*U12 + 2hla*c*U13 + 2klb*c*U23)] 



110 



Table B-5: Fractional coordinates and isotropic-thermal parameters (A2) 


for the H atoms 


of c 


impound 14. 








Atom 


X 


V 


z 


U 


H3 


-0.0103(12) 


0.4344(8) 


0.3102(9) 


0.08 


H4 


-0.1961(12) 


0.4370(9) 


0.3814(10) 


0.08 


H5 


-0.2502(13) 


0.3346(9) 


0.4706(10) 


0.08 


H6 


-0.1163(13) 


0.2300(9) 


0.4988(9) 


0.08 


H8 


0.3616(13) 


0.1291(8) 


0.1539(11) 


0.08 


H9 


0.555(2) 


0.0746(9) 


0.1207(13) 


0.08 


H10 


0.750(2) 


0.0624(10) 


0.252(2) 


0.08 


Hll 


0.7571(15) 


0.1085(10) 


0.414(2) 


0.08 


H12 


0.5645(14) 


0.1622(9) 


0.4508(12) 


0.08 


H13a 


0.342(2) 


0.0673(10) 


0.6077(12) 


0.08 


H13b 


0.385(2) 


0.1270(10) 


0.5363(12) 


0.08 


H13c 


0.286(2) 


0.0628(10) 


0.4878(12) 


0.08 


H14a 


0.060(2) 


0.0656(9) 


0.6315(13) 


0.08 


H14b 


0.010(2) 


0.0603(9) 


0.5112(13) 


0.08 


H14c 


-0.045(2) 


0.1236(9) 


0.5712(13) 


0.08 


H15a 


0.242(2) 


0.1955(10) 


0.7262(11) 


0.08 


H15b 


0.138(2) 


0.2527(10) 


0.6640(11) 


0.08 


H15c 


0.286(2) 


0.2541(10) 


0.6534(11) 


0.08 


H16a 


0.5103(15) 


0.3958(11) 


0.3241(14) 


0.08 


H16b 


0.4410(15) 


0.3215(11) 


0.2764(14) 


0.08 


H16c 


0.4800(15) 


0.3324(11) 


0.3963(14) 


0.08 


H17a 


0.274(2) 


0.4860(10) 


0.1915(11) 


0.08 


H17b 


0.128(2) 


0.4636(10) 


0.1972(11) 


0.08 


H17c 


0.212(2) 


0.4097(10) 


0.1446(11) 


0.08 


H18a 


0.355(2) 


0.5033(10) 


0.4297(11) 


0.08 


H18b 


0.335(2) 


0.4353(10) 


0.4983(11) 


0.08 


H18c 


0.210(2) 


0.4803(10) 


0.4359(11) 


0.08 



Ill 



1 


2 


3 


1-2 


1-2-3 


H3 


C3 


C4 


0.96(2) 


121.(2) 


H3 


C3 


C2 




120.7(15) 


H4 


C4 


C5 


0.96(2) 


119.(2) 


H4 


C4 


C3 




119.(2) 


H5 


C5 


C6 


0.96(2) 


120.(2) 


H5 


C5 


C4 




120.(2) 


H6 


C6 


CI 


0.96(2) 


120.(2) 


H6 


C6 


C5 




120.(2) 


H8 


C8 


C9 


0.96(2) 


121.(2) 


H8 


C8 


C7 




121.(2) 


H9 


C9 


CIO 


0.96(3) 


120.(2) 


H9 


C9 


C8 




120.(2) 


H10 


CIO 


Cll 


0.96(3) 


120.(2) 


HIO 


CIO 


C9 




120.(2) 


Hll 


Cll 


C12 


0.96(2) 


120.(2) 


Hll 


Cll 


CIO 




120.(2) 


H12 


C12 


C7 


0.96(2) 


120.(2) 


H12 


C12 


Cll 




120.(2) 


H13a 


C13 


H13b 


0.96(2) 


109.(2) 


H13a 


C13 


H13c 




109.(2) 


H13a 


C13 


Sil 




109.(2) 


H13b 


C13 


H13c 


0.96(3) 


109.(2) 


H13b 


C13 


Sil 




109.(2) 


H13c 


C13 


Sil 


0.96(2) 


109.(2) 


H14a 


C14 


H14b 


0.96(2) 


109.(2) 


H14a 


C14 


H14c 




109.(2) 


H14a 


C14 


Sil 




109.5(15) 


H14b 


C14 


H14c 


0.96(2) 


109.(2) 


H14b 


C14 


Sil 




109.(2) 


H14c 


C14 


Sil 


0.96(2) 


109.(2) 


H15a 


C15 


H15b 


0.96(2) 


109.(2) 


H15a 


C15 


H15c 




109.(2) 


H15a 


C15 


Sil 




109.(2) 


H15b 


C15 


H15c 


0.96(3) 


109.(2) 


H15b 


C15 


Sil 




109.5(14) 


H15c 


C15 


Sil 


0.96(3) 


110.(2) 


H16a 


C16 


H16b 


0.96(3) 


109.(2) 


H16a 


C16 


HI 6c 




109.(2) 


H16a 


C16 


Si2 




109.(2) 


HI 6b 


C16 


H16c 


0.96(3) 


109.(2) 


H16b 


C16 


Si2 




109.5(14) 


HI 6c 


C16 


Si2 


0.96(3) 


109.(2) 


H17a 


C17 


H17b 


0.96(2) 


109.(2) 


H17a 


C17 


H17c 




109.(2) 


H17a 


C17 


Si2 




109.5(13) 


H17b 


C17 


HI 7c 


0.96(2) 


109.(2) 



112 



Table B-6 continued. 



H17b 


C17 


Si2 


H17c 


C17 


Si2 


H18a 


C18 


H18b 


H18a 


C18 


H18c 


H18a 


C18 


Si2 


H18b 


C18 


H18c 


H18b 


C18 


Si2 


H18c 


C18 


Si2 



109.(2) 
0.96(2) 109.(2) 

0.96(2) 109.(2) 

109.(2) 

109.(2) 
0.96(2) 109.(2) 

109.(2) 
0.96(2) 109.5(14) 



113 




Crvstallographic Data for WfNPh^CbiTMe^rfMe^ SiNbCgFLil. 21 



Table B-7. Crystallographic Data. 



A. Crystal data (298 K) 

a, A 

b, A 

c, A 


21 

9.562 (1) 
10.277 (1) 
14.920 (2) 


a, deg. 


82.15 (1) 


p\ deg. 


80.18 (1) 


y, deg. 


80.41 (1) 


v,A 3 


1415.6 (3) 


J ca ic,gcm- 3 (298K) 

Empirical formula 

Formula wt, g 

Crystal system 

Space group 

Z 

F(000), electrons 


1.578 

C2iH 36 N 3 PCl2W 

672.43 

Triclinic 

P-1 

2 

668.0 


Crystal size (mm 3 ) 


0.25x0.10x0.09 


B. Data collection (298 K) 




Radiation, X (A) 


Mo-K a , 0.71073 


Mode 


u)- scan 


Scan range 


Symmetrically over 1.2° about 




Kai,2 maximum 


Background 


offset 1.0 and -1.0 in co from 




Kai,2 maxuTmrn 


Scan rate, deg. min." 1 


3-6 


28 range, deg. 
Range ofhkl 


3-45 
< h < 11 
-12 < k < 12 
-17 < I < 17 


Total reflections measured 
Unique reflections 


5312 
4981 


Absorption coeff. |i (Mo-K a ), cm" 1 
Min. & Max. Transmission 


4.42 

0.34906, 0.75350 


C. Structure refinement 

S, Goodness-of-fit 


1.2810 


Reflections used, I > 2a(I) 
No. of variables 
R, wR* (%) 

Rint. (%) 
Max. shift/esd 


4224 

271 

0.0408, 0.0426 

0.0149 

0.0005 



114 



115 



Supplementary Table 1 continued. 

min. peak in diff. four, map (e A" 3 ) - 1 .280 

max. peak in diff. four, map (e A" 3 ) 0.823 

* Relevant expressions are as follows, where in the footnote F and F c represent, 
respectively, the observed and calculated structure-factor amplitudes. 

Function minimized was w(IF l - IF C I) 2 , where w= (g(F))~ 2 

R = I(IIF l-IF c ll)/IIFol 

wR = [Iw(IF l - IF C I) 2 / I IFqI 2 ] 1 / 2 

S^tSwOFol-IFcl^/tm-n)] 1 / 2 



116 



Table B-8: Fractional coordinates and equivalent isotropic a thermal parameters (A^) for 
the non-H atoms of compound 21. 



Atom 



w 


0.12434(3) 


Cll 


0.3444(2) 


C12 


0.1471(2) 


P 


0.0480(3) 


Sil 


0.1579(2) 


Si2 


-0.1611(2) 


Nl 


0.0590(5) 


N2 


-0.0803(5) 


N3 


0.2226(6) 


CI 


-0.0875(6) 


C2 


-0.1635(7) 


C3 


-0.3100(8) 


C4 


-0.3805(8) 


C5 


-0.3075(8) 


C6 


-0.1616(8) 


C7 


0.3211(7) 


C8 


0.3295(10) 


C9 


0.4230(12) 


CIO 


0.5067(11) 


Cll 


0.4990(11) 


C12 


0.4076(9) 


C13 


0.0412(9) 


C14 


0.3150(8) 


C15 


0.2179(9) 


C16 


-0.3014(9) 


C17 


-0.0214(9) 


C18 


-0.2416(10) 


C19 


0.0354(13) 


C20 


0.1727(11) 


C21 


-0.1202(11) 



0.18104(3) 

0.2738(2) 

0.2147(2) 

0.4471(2) 

0.1751(2) 

0.0550(2) 

0.2082(6) 

0.1576(6) 

0.0219(6) 

0.2593(7) 

0.2302(7) 

0.2741(8) 

0.3426(9) 

0.3702(8) 

0.3299(8) 

-0.0877(8) 

-0.2036(10) 

-0.3135(11) 

-0.3108(13) 

-0.1985(14) 

-0.0843(11) 

0.1159(9) 

0.0453(9) 

0.3319(9) 

-0.0258(10) 

-0.0765(9) 

0.1603(10) 

0.5472(10) 

0.5247(10) 

0.4987(12) 



0.23475(2) 

0.23418(14) 

0.06792(12) 

0.1953(2) 

0.46064(14) 

0.18439(14) 

0.3671(3) 

0.2443(4) 

0.2314(4) 

0.3790(5) 

0.3112(5) 

0.3181(5) 

0.3898(7) 

0.4552(6) 

0.4507(5) 

0.2074(5) 

0.2659(7) 

0.2402(10) 

0.1580(10) 

0.1002(8) 

0.1239(6) 

0.5674(5) 

0.4378(6) 

0.4779(6) 

0.2649(6) 

0.1388(6) 

0.0909(6) 

0.2883(7) 

0.1071(7) 

0.1528(9) 



U 



0.03253(10) 

0.0566(8) 

0.0544(8) 

0.0531(8) 

0.0414(7) 

0.0453(8) 

0.034(2) 

0.034(2) 

0.038(2) 

0.034(2) 

0.038(2) 

0.048(3) 

0.063(4) 

0.056(3) 

0.047(3) 

0.044(3) 

0.073(4) 

0.099(6) 

0.091(6) 

0.096(5) 

0.075(4) 

0.058(3) 

0.063(4) 

0.067(4) 

0.065(4) 

0.059(3) 

0.069(4) 

0.090(5) 

0.081(4) 

0.106(6) 



£For anisotropic atoms, the U value is U e q, calculated as U eq = 1/3 Ej£j Ujj ai* aj* Ay 
where Ajj is the dot product of the i th and j th direct space unit cell vectors. 



117 

Table B-9: Bond Lengths (A) and Angles (°) for the non-H atoms of compound 21. 

1-2 1-2-3 



Cll 


W 


C12 


2.449(2) 


92.43(7) 


Cll 


w 


P 




75.86(7) 


Cll 


w 


Nl 




91.2(2) 


Cll 


w 


N2 




163.5(2) 


Cll 


w 


N3 




90.4(2) 


Cll 


w 


CI 




111.4(2) 


C12 


w 


P 


2.443(2) 


75.70(7) 


C12 


w 


Nl 




161.0(2) 


C12 


w 


N2 




90.7(2) 


C12 


w 


N3 




91.2(2) 


C12 


w 


CI 




135.07(14) 


C12 


w 


C2 




109.9(2) 


P 


w 


Nl 


2.720(2) 


87.2(2) 


P 


w 


N2 




89.2(2) 


P 


w 


N3 




160.3(2) 


P 


w 


CI 




74.25(14) 


P 


w 


C2 




75.3(2) 


Nl 


vv 


N2 


2.010(5) 


80.8(2) 


Nl 


w 


N3 




107.4(2) 


Nl 


w 


CI 




28.3(2) 


Nl 


w 


C2 




56.8(2) 


N2 


w 


N3 


1.990(5) 


105.8(3) 


N2 


w 


CI 




56.5(2) 


N2 


w 


C2 




27.9(2) 


N3 


w 


CI 


1.747(6) 


124.6(2) 


N3 


w 


C2 




123.6(2) 


CI 


w 


C2 


2.797(6) 


29.7(2) 


C2 


w 


Cll 


2.785(6) 


137.4(2) 


Nl 


Sil 




1.781(6) 




CI 


Nl 


W 


1.402(8) 


108.8(4) 


CI 


Nl 


Sil 




121.6(4) 


w 


Nl 


Sil 




129.6(3) 


C2 


N2 


W 


1.387(9) 


109.8(5) 


C7 


N3 


w 


1.388(9) 


164.3(5) 


C2 


CI 


C6 


1.430(11) 


119.7(6) 


C2 


CI 


w 




74.7(4) 


C2 


CI 


Nl 




114.4(6) 


C6 


CI 


W 


1.399(10) 


160.3(6) 


C6 


CI 


Nl 




125.9(7) 


W 


CI 


Nl 




42.8(3) 


C3 


C2 


W 


1.389(9) 


159.9(5) 


C3 


C2 


N2 




126.3(7) 


C3 


C2 


CI 




118.8(6) 


W 


C2 


N2 




42.2(3) 


w 


C2 


CI 




75.6(3) 


N2 


C2 


CI 




114.9(5) 



118 



Table B-9 continued. 



C4 


C3 


C2 


1.377(12) 


120.3(8) 


C5 


C4 


C3 


1.376(14) 


120.9(7) 


C6 


C5 


C4 


1.380(11) 


120.9(8) 


CI 


C6 


C5 




119.4(8) 


C8 


C7 


C12 


1.377(12) 


118.9(8) 


C8 


C7 


N3 




120.2(7) 


C12 


C7 


N3 


1.372(11) 


120.8(7) 


C9 


C8 


C7 


1.373(14) 


120.0(9) 


CIO 


C9 


C8 


1.35(2) 


121.2(11) 


Cll 


CIO 


C9 


1.34(2) 


119.4(11) 


C12 


Cll 


CIO 


1.39(2) 


121.4(10) 


C7 


C12 


Cll 




119.1(9) 



119 



Table B-10: Anisotropic thermal parameters a for the non-H atoms of compound 21. 
Atom Ull U22 U33 U12 U13 U23 



W 

Cll 

C12 

P 

Sil 

Si2 

Nl 

N2 

N3 

CI 

C2 

C3 

C4 

C5 

C6 

C7 

C8 

C9 

CIO 

Cll 

C12 

C13 

C14 

C15 

C16 

C17 

C18 

C19 

C20 

C21 



0.0293(2) 

0.0403(10) 

0.0601(12) 

0.0638(14) 

0.0376(10) 

0.0453(12) 

0.030(3) 

0.033(3) 

0.038(3) 

0.025(3) 

0.030(3) 

0.037(4) 

0.032(4) 

0.050(5) 

0.042(4) 

0.029(4) 

0.072(6) 

0.087(8) 

0.062(7) 

0.066(7) 

0.064(6) 

0.067(5) 

0.042(4) 

0.062(5) 

0.058(5) 

0.070(6) 

0.068(6) 

0.151(11) 

0.107(8) 

0.078(7) 



0.0372(2) 

0.0696(15) 

0.0670(14) 

0.0431(13) 

0.0516(13) 

0.0555(14) 

0.040(3) 

0.036(3) 

0.041(4) 

0.039(4) 

0.040(4) 

0.054(5) 

0.063(6) 

0.052(5) 

0.053(5) 

0.048(5) 

0.063(7) 

0.056(7) 

0.083(9) 

0.139(12) 

0.101(8) 

0.067(6) 

0.083(7) 

0.078(7) 

0.078(7) 

0.054(5) 

0.092(8) 

0.050(6) 

0.064(7) 

0.086(9) 



0.0298(2) 

0.0610(13) 

0.0324(10) 

0.0489(12) 

0.0384(11) 

0.0396(11) 

0.031(3) 

0.033(3) 

0.033(3) 

0.040(4) 

0.042(4) 

0.054(5) 

0.091(7) 

0.062(5) 

0.046(4) 

0.053(5) 

0.075(7) 

0.135(11) 

0.128(11) 

0.071(7) 

0.044(5) 

0.043(5) 

0.060(5) 

0.074(6) 

0.069(6) 

0.059(5) 

0.051(5) 

0.063(6) 

0.068(6) 

0.140(11) 



-0.00271(10) 

-0.0191(10) 

-0.0052(10) 

-0.0067(10) 

-0.0085(9) 

-0.0103(10) 

-0.007(2) 

-0.000(2) 

-0.003(3) 

-0.006(3) 

-0.002(3) 

-0.003(4) 

0.011(4) 

0.001(4) 
-0.006(4) 

0.001(3) 

0.000(5) 

0.022(6) 

0.028(6) 

0.029(7) 

0.019(5) 
-0.013(5) 

0.005(4) 
-0.031(5) 
-0.032(5) 
-0.007(4) 
-0.003(5) 
-0.025(6) 
-0.035(6) 

0.005(6) 



-0.00254(10) 

-0.0036(9) 

-0.0014(8) 

-0.0066(10) 

-0.0094(8) 

-0.0135(9) 

-0.003(2) 

-0.009(2) 

-0.004(2) 

-0.002(3) 

-0.003(3) 

-0.011(3) 

-0.006(4) 

0.003(4) 
-0.002(3) 
-0.008(3) 

0.009(5) 
-0.004(8) 
-0.025(7) 

0.009(5) 

0.002(4) 
-0.012(4) 
-0.012(4) 
-0.011(5) 
-0.016(4) 
-0.017(4) 
-0.032(4) 

0.014(6) 
-0.003(6) 
-0.036(7) 



-0.00437 
-0.0024( 
-0.0048( 

0.0026( 
-0.0097( 
-0.0092( 
-0.003(3 
-0.003(3 
-0.005(3 
-0.006(3 
-0.006(3 
-0.011(4 
-0.024(5 
-0.016(4 
-0.013(4 
-0.009(4 
-0.009(5 

0.000(7 
-0.043(8 
-0.045(8 
-0.008(5 
-0.009(4 
-0.009(5 
-0.026(5 
-0.007(5 
-0.022(4 
-0.004(5 
-0.009(5 

0.016(5 

0.037(8 



11 

1) 
0) 
0) 
0) 
0) 



2 Uij are the mean-square amplitudes of vibration in A 2 from the general temperature factor expressk 
exp[-27t 2 (h 2 a* 2 Ul 1 + k 2 b* 2 U22 + l 2 c* 2 U33 + 2hka*b*U12 + 2hla*c*U13 + 2klb*c*U23)] 



120 



Table B-l 1: Fractional coordinates and isotropic thermal parameters (A 2) for the H atoms of 
compound 21. 



Atom 



H3 


-0.3623(8) 


H4 


-0.4819(8) 


H5 


-0.3587(8) 


H6 


-0.1115(8) 


H8 


0.2700(10) 


H9 


0.4288(12) 


H10 


0.5713(11) 


Hll 


0.5578(11) 


H12 


0.4051(9) 


H13a 


0.0954(9) 


H13b 


0.0082(9) 


H13c 


-0.0397(9) 


H14a 


0.3668(8) 


H14b 


0.3767(8) 


H14c 


0.2829(8) 


H15a 


0.2715(9) 


H15b 


0.1357(9) 


H15c 


0.2775(9) 


H16a 


-0.3437(9) 


H16b 


-0.3743(9) 


H16c 


-0.2585(9) 


H17a 


-0.0636(9) 


H17b 


0.0199(9) 


H17c 


0.0520(9) 


H18a 


-0.2849(10) 


H18b 


-0.1685(10) 


H18c 


-0.3134(10) 


H19a 


-0.0291(13) 


H19b 


0.0001(13) 


H19c 


0.1286(13) 


H20a 


0.2676(11) 


H20b 


0.1448(11) 


H20c 


0.1718(11) 


H21a 


-0.1953(11) 


H21b 


-0.1140(11) 


H21c 


-0.1409(11) 



u 



0.2566(8) 


0.2726(5) 


1.08 


0.3716(9) 


0.3941(7) 


1.08 


0.4179(8) 


0.5047(6) 


1.08 


0.3502(8) 


0.4964(5) 


1.08 


-0.2076(10) 


0.3247(7) 


1.08 


-0.3936(11) 


0.2817(10) 


1.08 


-0.3884(13) 


0.1408(10) 


1.08 


-0.1971(14) 


0.0412(8) 


1.08 


-0.0041(11) 


0.0825(6) 


1.08 


0.0983(9) 


0.6174(5) 


1.08 


0.0360(9) 


0.5586(5) 


1.08 


0.1830(9) 


0.5809(5) 


1.08 


0.0288(9) 


0.4889(6) 


1.08 


0.0748(9) 


0.3837(6) 


1.08 


-0.0351(9) 


0.4289(6) 


1.08 


0.3157(9) 


0.5282(6) 


1.08 


0.3978(9) 


0.4911(6) 


1.08 


0.3631(9) 


0.4233(6) 


1.08 


-0.0800(10) 


0.2325(6) 


1.08 


0.0413(10) 


0.2900(6) 


1.08 


-0.0801(10) 


0.3135(6) 


1.08 


-0.1313(9) 


0.1070(6) 


1.08 


-0.1298(9) 


0.1885(6) 


1.08 


-0.0366(9) 


0.0974(6) 


1.08 


0.1070(10) 


0.0585(6) 


1.08 


0.2008(10) 


0.0495(6) 


1.08 


0.2282(10) 


0.1158(6) 


1.08 


0.5146(10) 


0.3399(7) 


1.08 


0.6379(10) 


0.2688(7) 


1.08 


0.5422(10) 


0.3055(7) 


1.08 


0.5033(10) 


0.1231(7) 


1.08 


0.6192(10) 


0.1018(7) 


1.08 


0.4926(10) 


0.0498(7) 


1.08 


0.4626(12) 


0.1950(9) 


1.08 


0.4673(12) 


0.0943(9) 


1.08 


0.5939(12) 


0.1463(9) 


1.08 



121 



Table B-12: Bond Lengths (A) and Angles (°) of the H atoms of compound 21. 



1-2 



1-2-3 



H3 


C3 


C4 


0.960(12) 


119.9(8) 


H3 


C3 


C2 




119.8(8) 


H4 


C4 


C5 


0.960(11) 


119.6(11) 


H4 


C4 


C3 




119.6(11) 


H5 


C5 


C6 


0.960(12) 


119.6(10) 


H5 


C5 


C4 




119.5(9) 


H6 


C6 


CI 


0.960(12) 


120.3(8) 


H6 


C6 


C5 




120.3(9) 


H8 


C8 


C9 


0.960(13) 


120.0(11) 


H8 


C8 


C7 




120.0(10) 


H9 


C9 


CIO 


0.96(2) 


119.4(13) 


H9 


C9 


C8 




119.4(14) 


H10 


CIO 


Cll 


0.96(2) 


120.3(14) 


H10 


CIO 


C9 




120.3(14) 


Hll 


Cll 


C12 


0.960(15) 


119.2(14) 


Hll 


Cll 


CIO 




119.3(15) 


H12 


C12 


C7 


0.960(14) 


120.4(11) 


H12 


C12 


Cll 




120.5(10) 


H13a 


C13 


H13b 


0.960(12) 


109.5(11) 


H13a 


C13 


HI 3c 




109.5(11) 


H13b 


C13 


H13c 


0.960(14) 


109.5(11) 


H14a 


C14 


HI 4b 


0.960(13) 


109.5(11) 


H14a 


C14 


H14c 




109.5(12) 


H14b 


C14 


H14c 


0.960(11) 


109.5(12) 


H15a 


C15 


HI 5b 


0.960(14) 


109.5(12) 


H15a 


C15 


HI 5c 




109.5(12) 


H15b 


CI 5 


HI 5c 


0.960(12) 


109.5(11) 


H16a 


C16 


HI 6b 


0.960(15) 


109.5(11) 


H16a 


C16 


H16c 




109.5(12) 


H16b 


C16 


H16c 


0.960(12) 


109.5(12) 


H17a 


C17 


HI 7b 


0.960(14) 


109.5(11) 


H17a 


C17 


H17c 




109.5(11) 


H17b 


C17 


H17c 


0.960(12) 


109.5(11) 


H18a 


C18 


HI 8b 


0.96(2) 


109.5(12) 


H18a 


C18 


HI 8c 




109.5(12) 


H18b 


C18 


HI 8c 


0.960(13) 


109.5(13) 


H19a 


C19 


H19b 


0.960(14) 


109.5(13) 


H19a 


C19 


H19c 




109.5(13) 


H19b 


CI 9 


HI 9c 


0.960(13) 


109.5(15) 


H20a 


C20 


H20b 


0.96(2) 


109.5(15) 


H20a 


C20 


H20c 




109.5(13) 


H20b 


C20 


H20c 


0.960(14) 


109.5(12) 


H21a 


C21 


H21b 


0.96(2) 


109.(2) 


H21a 


C21 


H21c 




109.5(14) 


H21b 


C21 


H21c 


0.96(2) 


109.(2) 



122 




123 



Crystallogranhic data for WfNPh^rCHCMft^ CPMp^r^Mp.^iN^orgHlIJ^. 



Table B-13: Crvstallographic data for 36 

A. Crystal data (298 K) 

a, A 

b, A 

c, A 
a, deg. 

Meg. 
% deg. 

v,A 3 

dado g cm" 3 (298 K) 
Empirical formula 
Formula wt, g 
Crystal system 
Space group 
Z 

F(000), electrons 
Crystal size (mm 3 ) 

B. Data collection (298 K) 
Radiation, X (A) 

Mode 
Scan range 

Background 

Scan rate, deg. min." 1 

29 range, deg. 
Range ofhkl 



Total reflections measured 
Unique reflections 

Absorption coeff. \i (Mo-K a ), mm" 1 
Min. & Max. Transmission 

C. Structure refinement 

S, Goodness-of-fit 

Reflections used, I > 2a(I) 
No. of variables 
R, wR* (%) 

Rim. (%) 
Max. shift/esd 



36 

16.116(3) 
11.340(2) 
17.960(4) 

106.28(2) 

3151(1) 

1.416 

C 2 6H46N 3 Si2PW 

671.66 

Monoclinic 

P2i/c 

4 

1360 

0.38x0.21x0.13 



Mo-K a , 0.71073 

co-scan 

Symmetrically over 1.2° 
about K a i ^ maximum 

offset 1.0 and -1.0 in co from 
K a i 2 maximum 

3-6 



3-50 
< 
< 
-19 < 

6099 
5563 
3.81 

0.486, 0.618 



1.15 

3209 

298 

5.25%, 

4.00% 

0.0001 



h 
k 
I 



< 
< 

< 



19 
12 
19 



5.10% 



124 



Table B-13 continued. 

min. peak in diff. four, map (e A" 3 ) -1.10 

max. peak in diff. four, map (e A" 3 ) 1.40 

* Relevant expressions are as follows, where in the footnote F and F c represent, 
respectively, the observed and calculated structure-factor amplitudes. 

Function minimized was w(IF l - IF C I) 2 , where w= (a(F))" 2 

R = £(IIFol-IF c ll)/SFol 

wR = Ew(IFol - IF C I) 2 / IIFol 2 ] 1 / 2 

S = [Ew(IF l-IF c l) 2 /(m-n)] 1 / 2 



125 



Table B-14: Fractional coordinates and equivalent isotropic^-thermal parameters 
(A =) for the non-H atoms of compound 36 



Atom 



w 


-0.25717(3) 


PI 


-0.3548(2) 


Si2 


-0.1756(3) 


Si3 


-0.1715(3) 


Nl 


-0.3349(6) 


N2 


-0.2221(6) 


N3 


-0.2474(6) 


CI 


-0.4058(8) 


C2 


-0.4478(8) 


C3 


-0.5195(9) 


C4 


-0.5471(10) 


C5 


-0.5086(10) 


C6 


-0.4371(9) 


C7 


-0.2633(8) 


C8 


-0.2879(9) 


C9 


-0.3293(9) 


CIO 


-0.3502(10) 


Cll 


-0.3261(9) 


C12 


-0.2796(8) 


C13 


-0.1697(8) 


C14 


-0.1401(8) 


C15 


-0.1472(11) 


C16 


-0.1978(10) 


C17 


-0.0464(9) 


C18 


-0.1271(9) 


C19 


-0.2553(8) 


C20 


-0.0896(9) 


C21 


-0.1049(10) 


C22 


-0.1015(10) 


C23 


-0.2206(9) 


C24 


-0.4488(8) 


C25 


-0.3214(9) 


C26 


-0.4003(8) 


&For anisotropic 


atoms, the U vali 


Ajj where Ajj is 


the dot product o 



0.13867(5) 
0.2116(3) 
0.0067(4) 
-0.0438(4) 
0.2095(9) 
0.0012(8) 
-0.0029(9) 
0.2263(12) 
0.1309(14) 
0.149(2) 
0.263(2) 
0.354(2) 
0.3402(12) 
-0.0999(11) 
-0.2024(13) 
-0.2908(12) 
-0.2888(13) 
-0.1941(14) 
-0.1003(11) 
0.2529(11) 
0.3780(13) 
0.4449(13) 
0.4429(13) 
0.3786(14) 
0.1518(13) 
-0.0145(13) 
-0.1054(14) 
0.0828(14) 
-0.156(2) 
-0.1051(14) 
0.1170(13) 
0.2068(14) 
0.3587(12) 



0.03328(3) 

0.1098(2 

-0.1059(2 

0.1953(2 

-0.0450(6 

-0.0297(5 

0.1078(6 

-0.1088(7 

-0.1508(8 

-0.2139(8 

-0.2342(9 

-0.1924(8 

-0.1294(8 

-0.0138(7 

-0.0601(8 

-0.0398(9 

0.0297(9 

0.0771(9 

0.0602(7 

0.0663(7 

0.0621(8 

0.1341(9 

-0.0079(9 

0.0597(9 

-0.1067(7 

-0.2021(7 

-0.0931(9 

0.2422(8 

0.1742(9 

0.2697(8 

0.0819(9 

0.2147(7 

0.0893(8 



U 



0.0334(2) 

0.0443(14) 

0.046(2) 

0.050(2) 

0.040(4) 

0.034(4) 

0.043(4) 

0.040(5) 

0.053(6) 

0.074(7) 

0.073(8) 

0.064(6) 

0.054(6) 

0.037(5) 

0.055(6) 

0.057(7) 

0.062(7) 

0.061(7) 

0.039(5) 

0.043(5) 

0.052(6) 

0.089(9) 

0.081(8) 

0.081(8) 

0.066(6) 

0.055(6) 

0.089(8) 

0.080(7) 

0.108(9) 

0.083(8) 

0.072(7) 

0.071(7) 

0.058(6) 

Ts.! Q'^ Q '* 



126 



1 


2 


3 


1-2 


1-2-3 


PI 


W 


Nl 


2.502(4) 


82.8(4) 


PI 


W 


N2 




148.1(3) 


PI 


w 


N3 




81.2(3) 


Nl 


w 


N2 


1.789(9) 


98.4(4) 


Nl 


w 


N3 




140.1(4) 


Nl 


w 


C13 




103.6(5) 


N2 


w 


N3 


2.095(10) 


77.8(4) 


N2 


w 


C13 




113.0(5) 


N3 


w 


C13 


2.067(10) 


114.6(4) 


C13 


w 


PI 


1.884(13) 


97.5(4) 


C24 


PI 


C25 


1.809(13) 


104.6(7) 


C24 


PI 


C26 




103.2(6) 


C24 


PI 


W 




105.0(5) 


C25 


PI 


C26 


1.808(13) 


102.9(7) 


C25 


PI 


W 




120.9(5) 


C26 


PI 


W 


1.818(14) 


118.2(5) 


N2 


Si2 


C18 


1.736(11) 


108.6(6) 


N2 


Si2 


C19 




113.0(6) 


C18 


Si2 


C19 


1.82(2) 


107.2(6) 


C18 


Si2 


C20 




108.3(7) 


C19 


Si2 


C20 


1.856(11) 


109.1(7) 


C20 


Si2 


N2 


1.85(2) 


110.6(6) 


N3 


Si3 


C21 


1.761(9) 


111.8(6) 


N3 


Si3 


C22 




108.4(6) 


C21 


Si3 


C22 


1.85(2) 


109.0(7) 


C21 


Si3 


C23 




105.7(7) 


C22 


Si3 


C23 


1.81(2) 


107.5(8) 


C23 


Si3 


N3 


1.87(2) 


114.2(6) 


CI 


Nl 


W 


1.387(14) 


160.8(9) 


C7 


N2 


w 


1.39(2) 


106.6(8) 


C7 


N2 


Si2 




121.8(8) 


W 


N2 


Si2 




129.8(5) 


C12 


N3 


W 


1.40(2) 


105.6(7) 


C12 


N3 


Si3 




112.4(8) 


W 


N3 


Si3 




133.6(6) 


C2 


CI 


C6 


1.38(2) 


119.6(11) 


C2 


CI 


Nl 




120.5(11) 


C6 


CI 


Nl 


1.40(2) 


119.9(11) 


C3 


C2 


CI 


1.39(2) 


119.9(14) 


C4 


C3 


C2 


1.39(3) 


119.(2) 


C5 


C4 


C3 


1.33(2) 


121.1(13) 


C6 


C5 


C4 


1.38(2) 


122.(2) 


CI 


C6 


C5 




118.8(13) 


C8 


C7 


C12 


1.42(2) 


116.7(12) 


C8 


C7 


N2 




128.6(13) 


C12 


C7 


N2 


1.43(2) 


114.6(11) 



127 



Table B-15 continued 



C9 


C8 


C7 


1.31(2) 


122.9(15) 


CIO 


C9 


C8 


1.38(2) 


120.7(14) 


Cll 


CIO 


C9 


1.36(2) 


118.7(15) 


C12 


Cll 


CIO 


1.38(2) 


123.(2) 


N3 


C12 


C7 




115.6(12) 


N3 


C12 


Cll 




127.1(13) 


C7 


C12 


Cll 




117.3(12) 


C14 


C13 


W 


1.50(2) 


148.4(9) 


C15 


C14 


C16 


1.53(2) 


106.5(12) 


C15 


C14 


C17 




109.3(11) 


C15 


C14 


C13 




109.0(12) 


C16 


C14 


C17 


1.53(2) 


110.8(13) 


C16 


C14 


C13 




111.6(10) 


C17 


C14 


C13 


1.52(2) 


109.7(12) 



128 



Table B-16: Anisotropic thermal parameters^ for the non-H atoms of compound 36. 



Atom 



Ull 



w 


0.0377(3) 


PI 


0.048(2) 


Si2 


0.050(2) 


Si3 


0.050(2) 


Nl 


0.043(7) 


N2 


0.046(8) 


N3 


0.046(7) 


CI 


0.036(8) 


C2 


0.041(8) 


C3 


0.039(9) 


C4 


0.051(11) 


C5 


0.070(11) 


C6 


0.062(10) 


C7 


0.032(8) 


C8 


0.065(10) 


C9 


0.073(11) 


CIO 


0.077(12) 


Cll 


0.068(11) 


C12 


0.040(8) 


C13 


0.057(9) 


C14 


0.049(8) 


C15 


0.115(15) 


C16 


0.107(14) 


C17 


0.080(12) 


C18 


0.082(11) 


C19 


0.056(9) 


C20 


0.054(10) 


C21 


0.081(12) 


C22 


0.094(14) 


C23 


0.084(12) 


C24 


0.043(9) 


C25 


0.088(12) 


C26 


0.056(9) 



U22 



0.0318(3) 

0.045(2) 

0.052(3) 

0.052(3) 

0.035(7) 

0.028(6) 

0.038(7) 

0.039(8) 

0.056(10) 

0.11(2) 

0.12(2) 

0.060(10) 

0.049(11) 

0.036(9) 

0.048(10) 

0.024(8) 

0.034(9) 

0.057(11) 

0.034(9) 

0.044(9) 

0.045(10) 

0.032(10) 

0.042(10) 

0.065(12) 

0.076(12) 

0.070(11) 

0.11(2) 

0.090(13) 

0.12(2) 

0.10(2) 

0.071(13) 

0.085(12) 

0.058(9) 



U33 



0.0298(3) 

0.041(2) 

0.038(2) 

0.043(2) 

0.049(7) 

0.028(5) 

0.035(6) 

0.042(8) 

0.064(9) 

0.060(10) 

0.050(10) 

0.050(9) 

0.045(8) 

0.037(8) 

0.044(9) 

0.066(11) 

0.071(11) 

0.056(10) 

0.038(8) 

0.035(8) 

0.068(9) 

0.12(2) 

0.086(13) 

0.101(13) 

0.045(8) 

0.041(8) 

0.105(14) 

0.055(10) 

0.084(13) 

0.051(9) 

0.100(12) 

0.042(9) 

0.062(9) 



U12 



0.0030(4) 
0.000(2) 
0.004(2) 
0.005(2) 
0.010(5) 
0.002(5) 
0.003(6) 
-0.007(7) 
-0.009(8) 
-0.027(12) 
0.011(12) 
0.022(10) 
0.022(8) 
0.017(6) 
0.011(9) 
-0.018(8) 
0.001(8) 
-0.003(9) 
0.003(6) 
0.005(7) 
0.002(8) 
-0.010(10) 
0.004(10) 
-0.035(11) 
-0.004(11) 
-0.017(8) 
0.018(11) 
0.000(11) 
0.050(13) 
-0.006(11) 
0.007(8) 
0.027(10) 
0.011(9) 



U13 



0.0078(2) 

0.015(2 

0.012(2 

0.003(2 

0.024(6 

0.012(6 

-0.007(5 
0.003(6 
0.021(7 

-0.000(7 
0.012(8 

-0.001(8 
0.005(7 

-0.001(6 
0.005(8 
0.005(9 
0.014(9 
0.016(9 
0.001(6 
0.022(7 
0.024(7 
0.040(13) 
0.016(1 
0.031(10) 
0.026(8 
0.018(7 
0.026(9 

-0.001(9 

-0.023(1 

-0.007(8 
0.017(8 
0.019(8 
0.021(7 



) 



) 



U23 



0.0020(4) 
-0.001(2) 
-0.003(2) 
0.010(2) 
0.000(6) 
-0.006(5) 
0.016(6) 
0.001(7) 
-0.016(9) 
-0.011(13) 
0.025(12) 
0.018(9) 
0.014(7) 
0.006(6) 
-0.010(8) 
-0.002(8) 
0.006(9) 
-0.003(9) 
0.004(6) 
0.001(7) 
0.003(9) 
-0.022(10) 
0.015(10) 
0.008(11) 
0.006(9) 
-0.007(8) 
0.001(12) 
-0.000(10) 
-0.019(12) 
0.036(10) 
-0.012(10) 
0.011(9) 
-0.001(9) 



fl Uij are the mean-square amplitudes of vibration in A 2 from the general temperature factor 
expression 



exp[-27i 2 (h 2 a* 2 Ull + k 2 b* 2 U22 + l 2 c* 2 U33 + 2hka*b*U12 + 2hla*c*U13 + 2klb*c*U23)] 



129 



atoms of compound 36. 




J-^-J- AA.IM.J. l/iu W.J.J.JlWl.^.'.l. U 




Atom 


X 


v 


z 


u 


H2 


-0.42722 


0.05235 


-0.13645 


0.08 


H3 


-0.54983 


0.08306 


-0.24286 


0.08 


H4 


-0.59452 


0.27668 


-0.2795 


0.08 


H5 


-0.53144 


0.43207 


-0.20612 


0.08 


H6 


-0.40926 


0.40742 


-0.10044 


0.08 


H8 


-0.27357 


-0.20739 


-0.10841 


0.08 


H9 


-0.34533 


-0.35766 


-0.07361 


0.08 


H10 


-0.38132 


-0.35296 


0.04413 


0.08 


Hll 


-0.34192 


-0.19235 


0.12477 


0.08 


H13 


-0.12276 


0.21359 


0.10272 


0.08 


H15a 


-0.127290 


0.52443 


0.13252 


0.08 


H15b 


-0.11236 


0.40633 


0.17977 


0.08 


H15c 


-0.2064 


0.44583 


0.13525 


0.08 


H16a 


-0.19522 


0.4038 


-0.0546 


0.08 


H16b 


-0.17822 


0.52277 


-0.00837 


0.08 


H16c 


-0.25625 


0.44263 


-0.00474 


0.08 


H17a 


-0.02728 


0.45839 


0.05759 


0.08 


H17b 


-0.04195 


0.33658 


0.01462 


0.08 


H17c 


-0.01102 


0.34089 


0.10548 


0.08 


H18a 


-0.10114 


0.15618 


-0.1486 


0.08 


H18b 


-0.08369 


0.1644 


-0.05838 


0.08 


H18c 


-0.17096 


0.21134 


-0.11335 


0.08 


H19a 


-0.28215 


-0.09034 


-0.2038 


0.08 


H19b 


-0.22622 


-0.01003 


-0.24194 


0.08 


H19c 


-0.29855 


0.04603 


-0.21029 


0.08 


H20a 


-0.064660 


-0.10107 


-0.13569 


0.08 


H20b 


-0.11369 


-0.18242 


-0.09148 


0.08 


H20c 


-0.04566 


-0.09078 


-0.04542 


0.08 


H21a 


-0.07776 


0.11823 


0.20648 


0.08 


H21b 


-0.06128 


0.0559 


0.28723 


0.08 


H21c 


-0.14092 


0.13996 


0.25745 


0.08 


H22a 


-0.05966 


-0.17966 


0.22133 


0.08 


H22b 


-0.07223 


-0.12558 


0.13858 


0.08 


H22c 


-0.13551 


-0.22349 


0.15141 


0.08 


H23a 


-0.2563 


-0.17154 


0.24851 


0.08 


H23b 


-0.25518 


-0.04549 


0.28462 


0.08 


H23c 


-0.17553 


-0.129550 


0.3144 


0.08 


H24a 


-0.43103 


0.03618 


0.09071 


0.08 


H24b 


-0.47791 


0.1284 


0.02796 


0.08 


H24c 


-0.48724 


0.13625 


0.11238 


0.08 


H25a 


-0.29616 


0.13132 


0.23158 


0.08 


H25b 


-0.37078 


0.21877 


0.23374 


0.08 


H25c 


-0.2796 


0.26768 


0.23438 


0.08 


H26a 


-0.42015 


0.37045 


0.03424 


0.08 


H26b 


-0.35672 


0.41621 


0.11183 


0.08 


H26c 


-0.4479 


0.3673 


0.11118 


0.08 



130 



1 


2 


3 


1-2 


1-2-3 


H2 


C2 


C3 


0.960(15) 


120.1(14) 


H2 


C2 


CI 




120.0(11) 


H3 


C3 


C4 


0.96(2) 


120.5(13) 


H3 


C3 


C2 




121.(2) 


H4 


C4 


C5 


0.960(14) 


119.(2) 


H4 


C4 


C3 




120.(2) 


H5 


C5 


C6 


0.96(2) 


119.3(15) 


H5 


C5 


C4 




119.1(14) 


H6 


C6 


CI 


0.960(13) 


120.7(11) 


H6 


C6 


C5 




120.5(14) 


H8 


C8 


C9 


0.96(2) 


118.5(14) 


H8 


C8 


C7 




118.6(14) 


H9 


C9 


CIO 


0.960(14) 


119.6(15) 


H9 


C9 


C8 




120.(2) 


H10 


CIO 


Cll 


0.96(2) 


121.(2) 


H10 


CIO 


C9 




120.6(15) 


Hll 


Cll 


C12 


0.96(2) 


118.4(14) 


Hll 


Cll 


CIO 




118.(2) 


H13 


C13 


C14 


0.960(11) 


105.8(11) 


H13 


C13 


W 




105.8(10) 


H15a 


C15 


H15b 


0.960(15) 


109.5(14) 


H15a 


C15 


H15c 




109.(2) 


H15a 


C15 


C14 




110.(2) 


H15b 


C15 


H15c 


0.960(15) 


109.(2) 


H15b 


C15 


C14 




109.3(14) 


H15c 


C15 


C14 


0.96(2) 


109.5(13) 


H16a 


C16 


HI 6b 


0.96(2) 


109.(2) 


H16a 


C16 


HI 6c 




109.5(14) 


H16a 


C16 


C14 




109.4(14) 


H16b 


C16 


HI 6c 


0.96(2) 


109.(2) 


H16b 


C16 


C14 




109.7(12) 


HI 6c 


C16 


C14 


0.96(2) 


109.3(14) 


H17a 


C17 


H17b 


0.96(2) 


109.(2) 


H17a 


C17 


H17c 




109.5(13) 


H17a 


C17 


C14 




109.8(14) 


H17b 


C17 


H17c 


0.96(2) 


109.(2) 


H17b 


C17 


C14 




109.3(12) 


H17c 


C17 


C14 


0.960(14) 


109.3(15) 


H18a 


C18 


H18b 


0.960(15) 


109.5(14) 


H18a 


C18 


H18c 




109.5(13) 


H18a 


C18 


Si2 




109.5(11) 


H18b 


C18 


H18c 


0.960(11) 


109.5(14) 


H18b 


C18 


Si2 




109.4(11) 


H18c 


C18 


Si2 


0.960(14) 


109.5(11) 



131 



Table B-17 continued. 



H19a 


C19 


H19b 


H19a 


C19 


H19c 


H19a 


C19 


Si2 


H19b 


C19 


H19c 


H19b 


C19 


Si2 


H19c 


C19 


Si2 


H20a 


C20 


H20b 


H20a 


C20 


H20c 


H20a 


C20 


Si2 


H20b 


C20 


H20c 


H20b 


C20 


Si2 


H20c 


C20 


Si2 


H21a 


C21 


H21b 


H21a 


C21 


H21c 


H21a 


C21 


Si3 


H21b 


C21 


H21c 


H21b 


C21 


Si3 


H21c 


C21 


Si3 


H22a 


C22 


H22b 


H22a 


C22 


H22c 


H22a 


C22 


Si3 


H22b 


C22 


H22c 


H22b 


C22 


Si3 


H22c 


C22 


Si3 


H23a 


C23 


H23b 


H23a 


C23 


H23c 


H23a 


C23 


Si3 


H23b 


C23 


H23c 


H23b 


C23 


Si3 


H23c 


C23 


Si3 


H24a 


C24 


H24b 


H24a 


C24 


H24c 


H24a 


C24 


PI 


H24b 


C24 


H24c 


H24b 


C24 


PI 


H24c 


C24 


PI 


H25a 


C25 


H25b 


H25a 


C25 


H25c 


H25a 


C25 


PI 


H25b 


C25 


H25c 


H25b 


C25 


PI 


H25c 


C25 


PI 


H26a 


C26 


H26b 


H26a 


C26 


H26c 


H26a 


C26 


PI 


H26b 


C26 


H26c 


H26b 


C26 


PI 


H26c 


C26 


PI 



0.960(14) 



0.960(14) 

0.960(14) 
0.96(2) 



0.96(2) 

0.960(14) 
0.96(2) 



0.960(13) 

0.96(2) 
0.960(14) 



0.96(2) 

0.96(2) 
0.960(15) 



0.96(2) 

0.960(12) 
0.960(14) 



0.960(14) 

0.96(2) 
0.96(2) 



0.96(2) 

0.960(15) 
0.960(13) 



0.960(13) 
0.960(15) 



109.5(13) 

109.5(13) 

109.5(9) 

109.5(13) 

109.4(9) 

109.5(10) 

109.(2) 

109.5(14) 

109.4(12) 

109.(2) 

109.5(11) 

109.4(13) 

109.5(15) 

109.5(15) 

109.6(11) 

109.5(14) 

109.4(12) 

109.5(11) 

109.(2) 

109.(2) 

109.5(14) 

109.(2) 

109.5(13) 

109.4(13) 

109.5(15) 

109.5(15) 

109.5(11) 

109.5(14) 

109.4(12) 

109.4(12) 

109.5(14) 

109.(2) 

109.5(9) 

109.5(12) 

109.6(12) 

109.4(11) 

109.(2) 

109.5(13) 

109.4(11) 

109.5(15) 

109.4(9) 

109.6(12) 

109.5(14) 

109.5(11) 

109.6(11) 

109.5(14) 

109.4(9) 

109.5(11) 



132 




-3- 


CO 


cn 


CO 


o 


O 



133 



CrvstaUographic data for f rfMe^SiNbC^ m iWH^Uii-HYfi- 
NPh) 2 f rfMe^SiNb C^KU IWfCH^CMe^K 45 



Table B-18: CrvstaUographic data for 45 



A. Crystal data (298 K) 


45 


a, A 


11.430(1) 


b, A 


11.640(1) 


c, A 


19.012 (2) 


a, deg. 


96.52 (1) 


P, deg. 


92.39 (1) 


y, deg. 


104.44 (1) 


V,A3 


2427.2 (4) 


dcaic, g cm" 3 (298 K) 


1.532 


Empirical formula 


C4lH6 8 N6Si4W2 


Formula wt, g 


1125.07 


Crystal system 


Triclinic 


Space group 


P-l 


Z 


2 


F(000), electrons 


1120 


Crystal size (mm 3 ) 


0.34 x 0.30 x 0.25 


B. Data collection (298 K) 




Radiation, X (A) 


Mo-Ka, 0.71073 


Mode 


co-scan 


Scan range 


Symmetrically over 1.2° 




about K a i 2 maximum 


Background 


offset 1.0 and -1.0 in co from 




K al; 2 max i mum 


Scan rate, deg. min." 1 


3-6 


29 range, deg. 


3-45 


Range of h k I 


< h < 12 




-12 < k < 12 




-20 < I < 20 


Total reflections measured 


7033 


Unique reflections 


6235 


Absorption coeff. \i (Mo-K a ), cm" 1 


4.84 


Min. & Max. Transmission 


0.365, 0.537 


C. Structure refinement 




S, Goodness-of-fit 


1.11 


Reflections used, I > 2a(I) 


4878 


No. of variables 


482 


R, wR* (%) 


0.0293, 0.0328 



134 
Table B-18: Crystallographic data for 45. continued 

Rint. (%) 0.0119 

Max. shift/esd 0.0006 

min. peak in diff. four, map (e A" 3 ) -0.993 

max. peak in diff. four, map (e A" 3 ) 1 .63 1 

* Relevant expressions are as follows, where in the footnote F and F c represent, respectively, the 
observed and calculated structure-factor amplitudes. 

Function minimized was w(IF l - IF C I) 2 , where w= (g(F))~ 2 

R = I(HF l-IFcll)/ElF l 

wR = [Iw(IF l - IF C I) 2 / 1 IFqI 2 ] 1 ^ 2 

S = [Iw(IF l-IF c l) 2 /(m-n)] 1 / 2 



135 

Table B-19: Fractiona l coordinates and equivalent isotropic^-thermal parameters (kh for 
the non-H atoms of compound 45. 



Atom 



Wl 


0.23216(3) 


W2 


0.31577(3) 


Sil 


0.2917(2) 


Si2 


0.4317(3) 


Si3 


0.6162(2) 


Si4 


0.1192(2) 


Nl 


0.2352(5) 


N2 


0.3082(6) 


N3 


0.4762(6) 


N4 


0.2633(6) 


N5 


0.2759(5) 


N6 


0.1935(5) 


CI 


0.0445(6) 


C2 


-0.0453(8) 


C3 


-0.0743(9) 


C4 


-0.1649(8) 


C5 


-0.0001(10) 


C6 


0.2320(7) 


C7 


0.2721(7) 


C8 


0.2721(9) 


C9 


0.2320(10) 


CIO 


0.1907(10) 


Cll 


0.1911(9) 


C12 


0.5130(9) 


C13 


0.3790(12) 


C14 


0.5455(10) 


C15 


0.3523(9) 


C16 


0.1730(10) 


C17 


0.4230(9) 


C18 


0.1238(7) 


C19 


0.0357(7) 


C20 


-0.0338(9) 


C21 


-0.0141(11) 


C22 


0.0702(11) 


C23 


0.1406(9) 


C24 


0.2816(7) 


C25 


0.2324(7) 


C26 


0.2420(9) 


C27 


0.3013(9) 


C28 


0.3475(9) 


C29 


0.3375(8) 


C30 


0.4707(8) 


C31 


0.3588(7) 


C32 


0.3462(8) 


C33 


0.4433(10) 


C34 


0.5504(9) 


C35 


0.5655(8) 



0.11989(2) 
0.28833(3) 
0.2682(2) 
-0.0668(3) 
0.4336(2) 
0.3415(3) 
0.1410(5) 
-0.0138(5) 
0.4110(6) 
0.3718(6) 
0.1199(5) 
0.2825(5) 
0.0298(7) 
-0.0796(8) 
-0.0540(11) 
-0.1021(8) 
-0.1893(9) 
0.0299(7) 
-0.0532(7) 
-0.1637(8) 
-0.1926(9) 
-0.1117(9) 
-0.0001(8) 
0.0165(10) 
-0.2252(9) 
-0.0475(11) 
0.4132(7) 
0.2897(9) 
0.2387(9) 
0.3553(6) 
0.3128(8) 
0.3842(9) 
0.5007(10) 
0.5429(9) 
0.4723(8) 
0.0485(7) 
-0.0735(7) 
-0.1460(9) 
-0.0945(10) 
0.0266(10) 
0.0980(8) 
0.4899(7) 
0.4683(7) 
0.5419(7) 
0.6314(8) 
0.6531(8) 
0.5835(7) 



0.276090(10) 
0.20326(2) 
0.44958(12) 
0.26414(13) 
0.24674(14) 
0.07887(13) 
0.3831(3) 
0.2968(3) 
0.1965(3) 
0.1238(3) 
0.1713(3) 
0.2693(3) 
0.2408(4) 
0.2632(5) 
0.3389(5) 
0.2160(5) 
0.2519(8) 
0.4101(4) 
0.3643(4) 
0.3854(5) 
0.4503(5) 
0.4940(5) 
0.4745(4) 
0.1956(5) 
0.2240(6) 
0.3405(6) 
0.4146(5) 
0.5101(5) 
0.4989(5) 
0.2998(4) 
0.3446(4) 
0.3763(5) 
0.3617(6) 
0.3164(6) 
0.2865(5) 
0.1068(4) 
0.1008(4) 
0.0380(5) 
-0.0164(5) 
-0.0109(5) 
0.0506(4) 
0.1442(4) 
0.1047(4) 
0.0537(4) 
0.0403(5) 
0.0781(5) 
0.1294(5) 



U 



0.02849(12) 

0.03111(13) 

0.0485(9) 

0.0583(11) 

0.0563(10) 

0.0547(10) 

0.035(2) 

0.036(2) 

0.041(2) 

0.041(3) 

0.032(2) 

0.035(2) 

0.039(3) 

0.051(3) 

0.099(6) 

0.066(4) 

0.110(6) 

0.040(3) 

0.040(3) 

0.061(4) 

0.073(5) 

0.072(5) 

0.059(4) 

0.075(5) 

0.098(6) 

0.100(6) 

0.066(4) 

0.081(5) 

0.077(4) 

0.035(3) 

0.049(3) 

0.070(4) 

0.085(6) 

0.079(5) 

0.060(4) 

0.035(3) 

0.047(3) 

0.070(4) 

0.071(5) 

0.069(5) 

0.051(4) 

0.043(3) 

0.041(3) 

0.051(4) 

0.062(4) 

0.060(4) 

0.055(4) 



136 



Table B- 19 : continued. 



C36 


0.7328(9) 


0.4112(11) 


0.1852(6) 


0.099(6) 


C37 


0.6209(9) 


0.3282(10) 


0.3131(6) 


0.093(5) 


C38 


0.6523(10) 


0.5835(9) 


0.2994(5) 


0.088(5) 


C39 


0.0529(9) 


0.4724(10) 


0.0954(5) 


0.087(5) 


C40 


0.1251(9) 


0.2961(9) 


-0.0178(5) 


0.076(5) 


C41 


0.0148(8) 


0.2151(10) 


0.1134(6) 


0.093(5) 



2For anisotropic atoms, the U value is U eq , calculated as U eq = 1/3 LiXj Uy af af A{; 
where Ajj is the dot product of the i* and j* direct space unit cell vectors. 



137 



Table B-20: Bond Lengths (A) and Angles (Sj for the non-H atoms of compound 4$. 



1 


2 


3 


1-2 


1-2-3 


W2 


Wl 


HI 


2.5430(5) 


42.3(15) 


W2 


Wl 


Nl 




124.0(2) 


W2 


Wl 


N2 




127.1(2) 


W2 


Wl 


N5 




47.8(2) 


W2 


Wl 


N6 




47.6(2) 


HI 


Wl 


Nl 


2.19(5) 


95.5(13) 


HI 


Wl 


N2 




96.(2) 


HI 


Wl 


N5 




70.5(13) 


HI 


Wl 


N6 




72.(2) 


HI 


Wl 


CI 




153.4(15) 


Nl 


Wl 


N2 


2.019(6) 


80.4(2) 


Nl 


Wl 


N5 




165.3(2) 


Nl 


Wl 


N6 




92.7(2) 


Nl 


Wl 


CI 




104.7(3) 


N2 


Wl 


N5 


2.029(7) 


96.0(2) 


N2 


Wl 


N6 




165.6(2) 


N2 


Wl 


CI 




104.6(3) 


N5 


Wl 


N6 


2.075(6) 


87.4(2) 


N5 


Wl 


CI 




90.0(2) 


N6 


Wl 


CI 


2.064(6) 


89.4(3) 


CI 


Wl 


W2 


2.179(6) 


111.0(2) 


HI 


W2 


N3 


1.74(6) 


80.(2) 


HI 


W2 


N4 




161.(2) 


HI 


W2 


N5 




84.(2) 


HI 


W2 


N6 




87.(2) 


HI 


W2 


Wl 




58.(2) 


N3 


W2 


N4 


2.043(6) 


81.4(2) 


N3 


W2 


N5 




127.5(3) 


N3 


W2 


N6 




131.8(2) 


N3 


W2 


Wl 




137.9(2) 


N4 


W2 


N5 


2.034(7) 


108.0(2) 


N4 


W2 


N6 




105.0(3) 


N4 


W2 


Wl 




140.7(2) 


N5 


W2 


N6 


1.919(5) 


96.6(2) 


N5 


W2 


Wl 




53.2(2) 


N6 


W2 


Wl 


1.912(6) 


52.9(2) 


Nl 


Sil 


C15 


1.799(6) 


115.2(3) 


Nl 


Sil 


C16 




111.4(4) 


C15 


Sil 


C16 


1.865(9) 


107.2(5) 


C15 


Sil 


C17 




105.5(4) 


C16 


Sil 


C17 


1.860(11) 


111.2(5) 


C17 


Sil 


Nl 


1.861(11) 


106.2(4) 


N2 


Si2 


C12 


1.783(7) 


115.0(4) 


N2 


Si2 


C13 




110.6(5) 


C12 


Si2 


C13 


1.854(10) 


106.4(5) 


C12 


Si2 


C14 




105.8(5) 


C13 


Si2 


C14 


1.853(10) 


111.6(6) 


C14 


Si2 


N2 


1.863(11) 


107.2(4) 



138 



Table B-20: continued 



N3 


Si3 


C36 


N3 


Si3 


C37 


C36 


Si3 


C37 


C36 


Si3 


C38 


C37 


Si3 


C38 


C38 


Si3 


N3 


N4 


Si4 


C39 


N4 


Si4 


C40 


C39 


Si4 


C40 


C39 


Si4 


C41 


C40 


Si4 


C41 


C41 


Si4 


N4 


Wl 


HI 


W2 


C6 


Nl 




C7 


N2 


Si2 


C30 


N3 




C31 


N4 


Si4 


C24 


N5 




C18 


N6 




C3 


C2 


C4 


C4 


C2 


C5 


C5 


C2 


C3 


C7 


C6 


Cll 


C7 


C6 


Nl 


Cll 


C6 


Nl 


C8 


C7 


N2 


C8 


C7 


C6 


N2 


C7 


C6 


C9 


C8 


C7 


CIO 


C9 


C8 


Cll 


CIO 


C9 


C6 


Cll 


CIO 


C19 


C18 


C23 


C19 


C18 


N6 


C23 


C18 


N6 


C20 


C19 


C18 


C21 


C20 


C19 


C22 


C21 


C20 


C23 


C22 


C21 


C18 


C23 


C22 


C25 


C24 


C29 


C25 


C24 


N5 


C29 


C24 


N5 


C26 


C25 


C24 


C27 


C26 


C25 


C28 


C27 


C26 


C29 


C28 


C27 


C24 


C29 


C28 


C31 


C30 


C35 


C31 


C30 


N3 


C35 


C30 


N3 


C32 


C31 


N4 



1.773(7) 


108.6(4) 




116.2(4) 


1.857(12) 


104.5(6) 




114.1(5) 


1.865(12) 


104.9(5) 


1.850(10) 


108.7(4) 


1.758(7) 


110.7(4) 




111.2(4) 


1.866(13) 


111.6(5) 




106.5(5) 


1.862(9) 


106.9(4) 


1.852(11) 


109.7(4) 




80.(2) 


1.437(10) 




1.453(10) 


113.3(5) 


1.438(11) 




1.448(9) 


118.6(6) 


1.414(9) 




1.398(10) 




1.504(13) 


107.3(8) 


1.551(12) 


107.9(7) 


1.489(15) 


111.6(10) 


1.403(12) 


119.6(8) 




114.7(7) 


1.380(12) 


125.6(8) 


1.389(13) 


126.0(7) 




119.2(7) 




114.8(7) 


1.382(14) 


120.8(9) 


1.37(2) 


119.5(10) 


1.390(15) 


120.9(9) 




120.0(9) 


1.380(11) 


117.5(8) 




121.1(7) 


1.380(12) 


121.4(7) 


1.393(15) 


122.0(8) 


1.38(2) 


118.6(9) 


1.36(2) 


120.0(12) 


1.38(2) 


120.9(10) 




120.8(9) 


1.380(11) 


119.4(7) 




119.3(7) 


1.377(11) 


121.2(6) 


1.406(13) 


119.8(8) 


1.373(14) 


119.5(9) 


1.37(2) 


120.6(9) 


1.382(13) 


119.9(9) 




120.7(8) 


1.408(12) 


118.3(8) 




115.8(6) 


1.394(11) 


126.0(8) 


1.390(12) 


125.3(7) 









139 




Table B-20: continued. 








C32 


C31 


C30 




119.1(7) 


N4 


C31 


C30 




115.5(7) 


C33 


C32 


C31 


1.375(12) 


120.2(8) 


C34 


C33 


C32 


1.345(14) 


121.0(9) 


C35 


C34 


C33 


1.369(14) 


120.2(8) 


C30 


C35 


C34 




121.1(8) 



140 



Table B-21: Anisotropic thermal parameters^ for the non-H atoms of compound 45. 




Atom 


Ull 


U22 


U33 


U12 


U13 


U23 


Wl 


0.0342(2) 


0.0276(2) 


0.0243(2) 0.0076(2) 0.0029(2) 


0.00628(14 


W2 


0.0329(2) 


0.0308(2) 


0.0292(2) 0.0049(2) 0.0017(2) 


0.0094(2) 


Sil 


0.067(2) 


0.0446(14) 


0.0317(1 


3) 0.0152(13) -0.0072(12) 


-0.0039(11) 


Si2 


0.069(2) 


0.078(2) 


0.0453(1 


5) 0.047(2) 


0.0119(13) 


0.0162(13) 


Si3 


0.0396(14) 


0.063(2) 


0.058(2) 


-0.0024(1 


.2) -0.0028(12) 


0.0127(13) 


Si4 


0.0430(14) 


0.079(2) 


0.0471(1 


5) 0.0159(1 


.3) -0.0014(12) 


0.0320(14) 


Nl 


0.043(4) 


0.032(4) 


0.030(3) 


0.011(3) 


0.005(3) 


0.004(3) 


N2 


0.046(4) 


0.038(4) 


0.029(3) 


0.018(3) 


0.005(3) 


0.009(3) 


N3 


0.036(4) 


0.042(4) 


0.040(4) 


-0.000(3) 


0.006(3) 


0.009(3) 


N4 


0.041(4) 


0.043(4) 


0.039(4) 


0.007(3) 


0.008(3) 


0.014(3) 


N5 


0.032(3) 


0.031(3) 


0.034(4) 


0.010(3) 


-0.002(3) 


0.004(3) 


N6 


0.040(4) 


0.030(3) 


0.035(4) 


0.008(3) 


-0.005(3) 


0.005(3) 


CI 


0.032(4) 


0.043(5) 


0.037(5) 


-0.004(4) 


0.002(4) 


0.021(4) 


C2 


0.044(5) 


0.047(5) 


0.061(6) 


0.002(4) 


0.007(4) 


0.018(4) 


C3 


0.062(7) 


0.149(12) 


0.060(7) 


-0.026(7) 


0.007(6) 


0.026(7) 


C4 


0.045(6) 


0.064(6) 


0.073(7) 


-0.014(5) 


-0.003(5) 


0.009(5) 


C5 


0.067(8) 


0.056(7) 


0.197(1! 


i) -0.013(6) 


-0.014(9) 


0.042(8) 


C6 


0.055(5) 


0.040(5) 


0.028(4) 


0.013(4) 


0.009(4) 


0.007(4) 


C7 


0.045(5) 


0.047(5) 


0.032(4) 


0.011(4) 


-0.007(4) 


0.019(4) 


C8 


0.096(8) 


0.049(6) 


0.050(6) 


0.036(5) 


0.011(5) 


0.021(5) 


C9 


0.118(9) 


0.047(6) 


0.063(7) 


0.028(6) 


0.008(6) 


0.031(5) 


CIO 


0.100(8) 


0.075(7) 


0.044(6) 


0.017(6) 


0.015(6) 


0.032(6) 


Cll 


0.088(7) 


0.051(6) 


0.036(5) 


0.014(5) 


0.010(5) 


0.008(4) 


C12 


0.069(7) 


0.114(9) 


0.060(6) 


0.054(7) 


0.017(5) 


0.020(6) 


C13 


0.169(13) 


0.073(8) 


0.080(8) 


0.078(8) 


0.026(8) 


0.015(6) 


C14 


0.087(8) 


0.160(12) 


0.079(8) 


0.066(8) 


0.009(7) 


0.050(8) 


C15 


0.082(7) 


0.052(6) 


0.053(6) 


0.006(5) 


-0.020(5) 


-0.009(5) 


C16 


0.127(10) 


0.075(7) 


0.049(6) 


0.047(7) 


0.008(6) 


-0.001(5) 


C17 


0.084(8) 


0.071(7) 


0.064(7) 


0.006(6) 


-0.032(6) 


0.004(5) 


C18 


0.043(5) 


0.030(4) 


0.036(5) 


0.013(4) 


0.004(4) 


0.011(4) 


C19 


0.050(5) 


0.046(5) 


0.053(5) 


0.018(4) 


0.012(5) 


-0.005(4) 


C20 


0.058(6) 


0.080(8) 


0.073(7) 


0.025(6) 


0.013(5) 


-0.002(6) 


C21 


0.093(9) 


0.087(9) 


0.093(9) 


0.065(8) 


0.010(7) 


-0.009(7) 


C22 


0.109(10) 


0.055(7) 


0.089(8) 


0.051(7) 


-0.002(7) 


0.008(6) 


C23 


0.081(7) 


0.045(6) 


0.060(6) 


0.026(5) 


-0.002(5) 


0.007(5) 


C24 


0.036(4) 


0.036(5) 


0.035(5) 


0.013(4) 


-0.001(4) 


-0.003(4) 


C25 


0.042(5) 


0.055(6) 


0.040(5) 


0.006(4) 


0.003(4) 


0.001(4) 


C26 


0.072(7) 


0.057(6) 


0.070(7) 


0.012(5) 


-0.012(6) 


-0.014(6) 


C27 


0.084(8) 


0.093(9) 


0.037(6) 


0.034(7) 


-0.001(5) 


-0.012(6) 


C28 


0.090(8) 


0.091(8) 


0.039(6) 


0.047(7) 


0.022(5) 


0.004(5) 


C29 


0.073(6) 


0.061(6) 


0.029(5) 


0.029(5) 


0.022(4) 


0.018(4) 


C30 


0.053(6) 


0.032(5) 


0.051(5) 


0.015(4) 


0.025(5) 


0.013(4) 


C31 


0.050(5) 


0.039(5) 


0.042(5) 


0.019(4) 


0.016(4) 


0.016(4) 


C32 


0.068(6) 


0.045(5) 


0.047(5) 


0.021(5) 


0.003(5) 


0.021(4) 


C33 


0.085(8) 


0.051(6) 


0.054(6) 


0.012(6) 


0.021(6) 


0.029(5) 


C34 


0.067(7) 


0.051(6) 


0.061(6) 


0.001(5) 


0.029(6) 


0.022(5) 


C35 


0.060(6) 


0.043(5) 


0.058(6) 


0.000(5) 


0.017(5) 


0.010(5) 


C36 


0.052(7) 


0.123(10) 


0.121(11 


) 0.020(7) 


0.005(7) 


0.021(8) 



141 



Table B-21: continued. 



C37 
C38 
C39 

C40 
C41 



0.060(7) 
0.092(8) 
0.079(8) 
0.069(7) 
0.051(6) 



0.111(9) 

0.079(8) 

0.137(10) 

0.095(8) 

0.138(11) 



0.106(9) 
0.068(7) 
0.070(7) 
0.061(7) 
0.084(8) 



0.003(6) 

-0.022(6) 

0.058(7) 

0.018(6) 

-0.001(6) 



-0.025(6) 
-0.012(6) 
0.012(6) 
-0.017(5) 
-0.025(6) 



0.053(8) 
0.005(6) 
0.048(7) 
0.013(6) 
0.054(8) 



3 Uij are the mean-square amplitudes of vibration in A 2 from the general temperature factor expressic 
exp[-27t 2 (h 2 a* 2 Ull + k 2 b* 2 U22 + l 2 c* 2 U33 + 2hka*b*U12 + 2hla*c*U13 + 2klb*c*U23)] 



142 



Table B-22: Fractional coordinates and isotropic-thermal parameters (A2) for the H atoms of 
compound 45. 



Atom 



HI 


0.404(5) 


Hla 


0.04745 


Hlb 


0.00337 


H3a 


-0.00196 


H3b 


-0.1336 


H3c 


-0.10576 


H4a 


-0.19577 


H4b 


-0.22332 


H4c 


-0.14943 


H5a 


0.07397 


H5b 


0.01432 


H5c 


-0.05958 


H8 


0.30009 


H9 


0.23332 


H10 


0.16127 


Hll 


0.16265 


H12a 


0.4583 


H12b 


0.57922 


H12c 


0.54353 


H13a 


0.33616 


H13b 


0.44759 


H13c 


0.3261 


H14a 


0.61348 


H14b 


0.50937 


H14c 


0.57217 


H15a 


0.28831 


H15b 


0.4154 


H15c 


0.38447 


H16a 


0.1397 


H16b 


0.10986 


HI 6c 


0.20825 


H17a 


0.45662 


H17b 


0.48355 


H17c 


0.39661 


H19 


0.02177 


H20 


-0.09417 


H21 


-0.06001 


H22 


0.0811 


H23 


0.20209 


H25 


0.19178 


H26 


0.20735 


H27 


0.31052 


H28 


0.38671 


H29 


0.37004 


H32 


0.26931 


H33 


0.43462 


H34 


0.61651 



u 



0.253(5) 


0.270(3) 


0.011(14) 


0.00848 


0.1907 


0.08 


0.0922 


0.24846 


0.08 


-0.03966 


0.36964 


0.08 


-0.12142 


0.35135 


0.08 


0.01536 


0.34398 


0.08 


-0.032390 


0.22229 


0.08 


-0.16926 


0.22938 


0.08 


-0.11847 


0.16711 


0.08 


-0.17747 


0.28063 


0.08 


-0.20514 


0.20278 


0.08 


-0.25592 


0.26504 


0.08 


-0.22066 


0.35439 


0.08 


-0.26875 


0.46464 


0.08 


-0.13233 


0.53861 


0.08 


0.05609 


0.50585 


0.08 


0.00964 


0.15475 


0.08 


-0.01627 


0.18224 


0.08 


0.09928 


0.21444 


0.08 


-0.27209 


0.25773 


0.08 


-0.25452 


0.21104 


0.08 


-0.23108 


0.18246 


0.08 


-0.07528 


0.32471 


0.08 


-0.09287 


0.3767 


0.08 


0.03559 


0.35928 


0.08 


0.43343 


0.38841 


0.08 


0.40581 


0.38393 


0.08 


0.47481 


0.45347 


0.08 


0.21655 


0.52911 


0.08 


0.31189 


0.48418 


0.08 


0.35188 


0.54816 


0.08 


0.30448 


0.53524 


0.08 


0.2299 


0.46668 


0.08 


0.16662 


0.520260 


0.08 


0.23153 


0.3543 


0.08 


0.35316 


0.40767 


0.08 


0.55191 


0.38354 


0.08 


0.62294 


0.30494 


0.08 


0.50492 


0.256180 


0.08 


-0.10875 


0.13925 


0.08 


-0.23083 


0.03316 


0.08 


-0.14399 


-0.05873 


0.08 


0.06209 


-0.04978 


0.08 


0.18302 


0.05424 


0.08 


0.53024 


0.02782 


0.08 


0.67914 


0.00339 


0.08 


0.7177 


0.06909 


0.08 



143 



Table B-22: continued. 



H35 


0.64259 


0.59926 


0.15572 


0.08 


H36a 


0.73586 


0.46294 


0.14901 


0.08 


H36b 


0.71233 


0.32944 


0.16349 


0.08 


H36c 


0.81035 


0.4295 


0.21114 


0.08 


H37a 


0.70114 


0.34614 


0.33573 


0.08 


H37b 


0.59956 


0.24763 


0.28949 


0.08 


H37c 


0.56448 


0.33664 


0.34809 


0.08 


H38a 


0.65146 


0.6428 


0.26831 


0.08 


H38b 


0.7312 


0.59958 


0.32359 


0.08 


H38c 


0.59311 


0.58575 


0.33351 


0.08 


H39a 


0.10425 


0.5405 


0.07826 


0.08 


H39b 


0.04634 


0.49015 


0.14539 


0.08 


H39c 


-0.02609 


0.45386 


0.07097 


0.08 


H40a 


0.17851 


0.35955 


-0.03775 


0.08 


H40b 


0.04535 


0.27976 


-0.04094 


0.08 


H40c 


0.15442 


0.22545 


-0.02445 


0.08 


H41b 


-0.063710 


0.19883 


0.08873 


0.08 


H41c 


0.00847 


0.23537 


0.16321 


0.08 


H41D 


0.04561 


0.14539 


0.10611 


0.08 



144 



1 


2 


3 


1-2 


1-2-3 


Hla 


CI 


Hlb 


0.960(7) 


109.5(8) 


H3a 


C3 


H3b 


0.960(10) 


109.5(11) 


H3a 


C3 


H3c 




109.5(10) 


H3a 


C3 


C2 




109.5(9) 


H3b 


C3 


H3c 


0.960(11) 


109.5(11) 


H3b 


C3 


C2 




109.5(9) 


H3c 


C3 


C2 


0.960(13) 


109.4(10) 


H4a 


C4 


H4b 


0.960(10) 


109.5(9) 


H4a 


C4 


H4c 




109.5(10) 


H4a 


C4 


C2 




109.5(7) 


H4b 


C4 


H4c 


0.960(8) 


109.5(8) 


H4b 


C4 


C2 




109.5(9) 


H4c 


C4 


C2 


0.960(9) 


109.4(8) 


H5a 


C5 


H5b 


0.960(12) 


109.5(12) 


H5a 


C5 


H5c 




109.5(13) 


H5a 


C5 


C2 




109.4(9) 


H5b 


C5 


H5c 


0.960(14) 


109.5(10) 


H5b 


C5 


C2 




109.6(11) 


H5c 


C5 


C2 


0.960(10) 


109.4(10) 


H8 


C8 


C9 


0.960(10) 


119.6(9) 


H8 


C8 


C7 




119.6(9) 


H9 


C9 


CIO 


0.960(11) 


120.3(10) 


H9 


C9 


C8 




120.2(10) 


H10 


CIO 


Cll 


0.960(10) 


119.5(10) 


HIO 


CIO 


C9 




119.6(11) 


Hll 


Cll 


C6 


0.960(9) 


120.0(9) 


Hll 


Cll 


CIO 




120.0(9) 


H12a 


C12 


H12b 


0.960(10) 


109.5(9) 


HI 2a 


C12 


H12c 




109.5(11) 


H12a 


C12 


Si2 




109.5(7) 


HI 2b 


C12 


H12c 


0.960(11) 


109.5(9) 


H12b 


C12 


Si2 




109.4(9) 


HI 2c 


C12 


Si2 


0.960(10) 


109.5(7) 


H13a 


C13 


H13b 


0.960(11) 


109.5(12) 


H13a 


C13 


H13c 




109.5(11) 


H13a 


C13 


Si2 




109.4(8) 


H13b 


C13 


H13c 


0.960(14) 


109.5(11) 


H13b 


C13 


Si2 




109.5(8) 


H13c 


C13 


Si2 


0.960(12) 


109.5(9) 


H14a 


C14 


H14b 


0.960(13) 


109.5(13) 


H14a 


C14 


H14c 




109.5(10) 


H14a 


C14 


Si2 




109.4(8) 


H14b 


C14 


H14c 


0.960(11) 


109.5(10) 


H14b 


C14 


Si2 




109.5(8) 


H14c 


C14 


Si2 


0.960(12) 


109.5(10) 


H15a 


C15 


H15b 


0.960(10) 


109.5(9) 


H15a 


C15 


H15c 




109.5(9) 


H15b 


C15 


H15c 


0.960(10) 


109.5(9) 



145 



Table B-23: continued. 



H16a 


C16 


H16b 


0.960(10) 


109.5(10) 


H16a 


C16 


HI 6c 




109.5(9) 


H16b 


C16 


HI 6c 


0.960(12) 


109.5(11) 


H17a 


C17 


H17b 


0.960(9) 


109.5(9) 


H17a 


C17 


H17c 




109.5(9) 


H17b 


C17 


H17c 


0.960(10) 


109.5(11) 


H19 


C19 


C20 


0.960(9) 


119.0(8) 


H19 


C19 


C18 




119.0(9) 


H20 


C20 


C21 


0.960(10) 


120.6(11) 


H20 


C20 


C19 




120.7(10) 


H21 


C21 


C22 


0.960(13) 


119.9(12) 


H21 


C21 


C20 




120.0(11) 


H22 


C22 


C23 


0.960(11) 


119.5(11) 


H22 


C22 


C21 




119.6(13) 


H23 


C23 


C18 


0.960(9) 


119.6(10) 


H23 


C23 


C22 




119.6(9) 


H25 


C25 


C26 


0.960(8) 


120.1(8) 


H25 


C25 


C24 




120.1(8) 


H26 


C26 


C27 


0.960(10) 


120.3(10) 


H26 


C26 


C25 




120.3(10) 


H27 


C27 


C28 


0.960(10) 


119.7(10) 


H27 


C27 


C26 




119.7(10) 


H28 


C28 


C29 


0.960(10) 


120.1(10) 


H28 


C28 


C27 




120.0(10) 


H29 


C29 


C24 


0.960(9) 


119.7(8) 


H29 


C29 


C28 




119.6(8) 


H32 


C32 


C33 


0.960(9) 


119.9(9) 


H32 


C32 


C31 




119.9(8) 


H33 


C33 


C34 


0.960(10) 


119.5(9) 


H33 


C33 


C32 




119.5(10) 


H34 


C34 


C35 


0.960(9) 


119.9(10) 


H34 


C34 


C33 




119.9(10) 


H35 


C35 


C30 


0.960(9) 


119.4(9) 


H35 


C35 


C34 




119.5(8) 


H36a 


C36 


H36b 


0.960(13) 


109.5(11) 


H36a 


C36 


H36c 




109.5(10) 


H36b 


C36 


H36c 


0.960(12) 


109.5(13) 


H37a 


C37 


H37b 


0.960(10) 


109.5(12) 


H37a 


C37 


H37c 




109.5(11) 


H37b 


C37 


H37c 


0.960(11) 


109.5(10) 


H38a 


C38 


H38b 


0.960(11) 


109.5(9) 


H38a 


C38 


H38c 




109.5(12) 


H38b 


C38 


H38c 


0.960(11) 


109.5(10) 


H39a 


C39 


H39b 


0.960(11) 


109.5(10) 


H39a 


C39 


H39c 




109.5(12) 


H39a 


C39 


Si4 




109.5(9) 


H39b 


C39 


H39c 


0.960(10) 


109.5(11) 


H39b 


C39 


Si4 




109.5(9) 


H39c 


C39 


Si4 


0.960(10) 


109.5(8) 



146 



Table B-23: continued. 



H40a 


C40 


H40b 


H40a 


C40 


H40c 


H40a 


C40 


Si4 


H40b 


C40 


H40c 


H40b 


C40 


Si4 


H40c 


C40 


Si4 


H41b 


C41 


H41c 


H41b 


C41 


H41D 


H41b 


C41 


Si4 


H41c 


C41 


H41D 


H41c 


C41 


Si4 


H41D 


C41 


Si4 



0.960(10) 


109.5(10) 




109.5(10) 




109.5(7) 


0.960(10) 


109.5(9) 




109.5(8) 


0.960(12) 


109.5(8) 


0.960(10) 


109.5(10) 




109.5(10) 




109.5(9) 


0.960(11) 


109.5(12) 




109.5(7) 


0.960(12) 


109.4(8) 



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BIOGRAPHICAL SKETCH 

Daniel David VanderLende became enamored with chemistry while testing 
pool water samples for Acme Pool Service in the summer of 1984. The challenge 
presented to him by the excellent teaching of Donald Hopwood at Creston High School 
inspired Dan to continue his chemical education at the College of Wooster. Dr. Ted 
Williams took the time to provoke, inspire, tolerate, and nurture Dan as both a chemist and 
a person. Dr. Paul Gaus introduced Dan to synthetic organometallic chemistry in 1989 and 
instilled in him the pride and perseverance to make air-sensitive materials. Paul also 
explained to Dan that graduate school wasn't for just the A' student. Graduate school, 
according to Dr. Gaus, was for the person who wanted to give what it took to get the job 
done. He proved to be correct. 

After considering offers from numerous professional sports teams, Dan realized 
that his graduate education was more important. After spending the summer of 1990 in 
Wooster as a PRF Researcher, Dan's love of synthesis drove him to the University of 
Florida. Once Dan recovered from a debilitating bicycle/auto accident, he began to create 
new molecules in the laboratory of his mentor, Dr. Jim Boncella. 

Over four years, Dan made strides in group(lO) amide chemistry as well as high 
oxidation state tungsten chemistry. Although few people understand what drives Dan to 
spend long hours trying to prepare new compounds, the reason is simple. Dan will never 
hold the world record in the 100 yard dash, hit 716 home runs, or be the first man on the 
moon. But the feeling might be the same as standing there holding a Schlenk tube 
containing crystals of W(NPh)Cl 2 (Me3SiN)2C6H4. 



153 






I certify that I have read this study and that in my opinion it conforms to acceptable 
standards of scholarly presentation and is fully adequate, in scope and quality as a thesis 
for the degree of Doctor of Philosophy. 



t&mPh fpHh^J^U 




ames M. Boncella, Chair 
Associate Professor of Chemistry 

I certify that I have read this study and that in my opinion it conforms to acceptable 
standards of scholarly presentation and is fully adequate, in scope and quality, as a thesis 
for the degree of Doctor of Philosophy. 




David E. Richardson 
Professor of Chemistry 

I certify that I have read this study and that in my opinion it conforms to acceptable 
standards of scholarly presentation and is fully adequate, in scope and quality, as a thesis 
for the degree of Doctor of Philosophy. 




William M. Jones 

Disinguished Service"Professor of 

Chemistry 

I certify that I have read this study and that in my opinion it conforms to acceptable 
standards of scholarly presentation and is fully adequate, in scope and quality, as a thesis 
for the degree of Doctor of Philosophy. 

Kenneth B. Wagener I 

Professor of Chemistry 

I certify that I have read this study and that in my opinion it conforms to acceptable 
standards of scholarly presentation and is fully adequate, in scope and quality, as a thesis 
for the degree of Doctor of Philosophy. 




Anthony/6. Brennan 
Assistant Professor of Materials 
Science and Engineering 



This thesis was submitted to the Graduate Faculty of the of the Department of 
Chemistry in the College of Liberal Arts and Sciences and to the Graduate School and was 
accepted as partial fulfillment of the requirements for the degree of Doctor of Philosophy 



December, 1994 



Dean, Graduate School